diff --git a/_config/extensions.yml b/_config/extensions.yml
new file mode 100644
index 0000000..e6b672d
--- /dev/null
+++ b/_config/extensions.yml
@@ -0,0 +1,9 @@
+---
+Name: silverstripe-serialized-dataobject-extensions
+After: 'framework/*','cms/*'
+---
+Form:
+  extensions:
+    - 'zauberfisch\SerializedDataObject\Form\FormExtension'
+  url_handlers:
+    'field/$FieldName!': 'handleFieldArrayList'
diff --git a/javascript/ArrayListField.js b/javascript/ArrayListField.js
index 3653870..9008121 100644
--- a/javascript/ArrayListField.js
+++ b/javascript/ArrayListField.js
@@ -37,10 +37,10 @@
 				recordList = field.getRecordList(),
 				_this = this,
 				newIndex = recordList.find('.record').length,
-				url = field.data('add-record-url') + '?index=' + newIndex;
+				url = field.data('add-record-url');
 			this.addClass('loading');
 			this.getRootForm().addClass('changed');
-			$.get(url, function (content) {
+			$.get(url, {'index': newIndex}, function (content) {
 				recordList.append(content);
 				_this.removeClass('loading');
 				_this.blur();
diff --git a/src/Form/ArrayListField.php b/src/Form/ArrayListField.php
index a23aa4c..6a62546 100644
--- a/src/Form/ArrayListField.php
+++ b/src/Form/ArrayListField.php
@@ -10,6 +10,7 @@
 
 class ArrayListField extends FormField {
 	protected $recordFieldsCallback;
+	protected $recordFieldsUpdateCallback;
 	protected $recordClassName;
 	protected $orderable = false;
 	
@@ -147,6 +148,10 @@ protected function getRecordFields($index, AbstractDataObject $record = null) {
 				->addExtraClass('controls')
 		);
 		$this->prefixRecordFields($index, $recordFields);
+		$callback = $this->getRecordFieldsUpdateCallback();
+		if ($callback) {
+			$recordFields = call_user_func($callback, $recordFields, $this, $record);
+		}
 		return (new \CompositeField($recordFields))->addExtraClass('record');
 	}
 	
@@ -244,6 +249,20 @@ public function getPrefixedRecordFieldName($index, $fieldName) {
 		return sprintf('%s[%s][%s]', $this->getName(), $index, $fieldName);
 	}
 	
+	public function handleSubField($fullFieldName) {
+		$str = substr($fullFieldName, strlen($this->getName()));
+		if (preg_match('/^\[(\d*)\]/', $str, $matches)) {
+			$fields = $this->getRecordFields($matches[1]);
+			$subField = $fields->FieldList()->dataFieldByName($fullFieldName);
+			if (!$subField) {
+				$subField = $fields->FieldList()->fieldByName($fullFieldName);
+			}
+			$subField->setForm($this->getForm());
+			return $subField;
+		}
+		return null;
+	}
+	
 	/**
 	 * @param \DataObjectInterface $record
 	 */
@@ -285,7 +304,7 @@ public function setForm($form) {
 	}
 	
 	/**
-	 * @param mixed $recordFieldsCallback
+	 * @param callable $recordFieldsCallback
 	 * @return ArrayListField
 	 */
 	public function setRecordFieldsCallback($recordFieldsCallback) {
@@ -294,7 +313,7 @@ public function setRecordFieldsCallback($recordFieldsCallback) {
 	}
 	
 	/**
-	 * @return mixed
+	 * @return callable
 	 */
 	public function getRecordFieldsCallback() {
 		$callback = $this->recordFieldsCallback;
@@ -314,4 +333,20 @@ public function getRecordFieldsCallback() {
 		}
 		return $callback;
 	}
+	
+	/**
+	 * @param callable $recordFieldsUpdateCallback
+	 * @return ArrayListField
+	 */
+	public function setRecordFieldsUpdateCallback($recordFieldsUpdateCallback) {
+		$this->recordFieldsUpdateCallback = $recordFieldsUpdateCallback;
+		return $this;
+	}
+	
+	/**
+	 * @return callable|null
+	 */
+	public function getRecordFieldsUpdateCallback() {
+		return $this->recordFieldsUpdateCallback;
+	}
 }
diff --git a/src/Form/FormExtension.php b/src/Form/FormExtension.php
new file mode 100644
index 0000000..4c6db9a
--- /dev/null
+++ b/src/Form/FormExtension.php
@@ -0,0 +1,34 @@
+<?php
+
+namespace zauberfisch\SerializedDataObject\Form;
+
+class FormExtension extends \Extension {
+	private static $allowed_actions = [
+		'handleFieldArrayList',
+	];
+//	private static $url_handlers = [
+//		'field/$FieldName!' => 'handleFieldArrayList',
+//	];
+
+	
+	/**
+	 * @param \SS_HTTPRequest $request
+	 * @return \FormField
+	 */
+	public function handleFieldArrayList($request) {
+		$field = $this->owner->handleField($request);
+		if (!$field) {
+			$fieldName = $request->param('FieldName');
+			foreach($this->owner->Fields()->dataFields() as $dataField) {
+				/** @var \FormField|ArrayListField $dataField */
+				if ($dataField->is_a(ArrayListField::class)) {
+					if (strpos($fieldName, $dataField->getName()) == 0) {
+						$field = $dataField->handleSubField($fieldName);
+						break;
+					}
+				}
+			}
+		}
+		return $field;
+	}
+}
diff --git a/src/Form/ProxyArrayListField.php b/src/Form/ProxyArrayListField.php
new file mode 100644
index 0000000..92417aa
--- /dev/null
+++ b/src/Form/ProxyArrayListField.php
@@ -0,0 +1,58 @@
+<?php
+
+namespace zauberfisch\SerializedDataObject\Form;
+
+use zauberfisch\NamespaceTemplates\Form\CompositeField;
+
+class ProxyArrayListField extends CompositeField {
+	public function __construct($name, $title = null, $recordClassName) {
+		$_this = $this;
+		parent::__construct([
+			(new ArrayListField($name, $title, $recordClassName))
+				->setRecordFieldsUpdateCallback(function ($fields, $listField, $record = null) use ($_this) {
+					foreach($fields as $field) {
+						$_this->push(new ProxyArrayListField_FieldProxy($field));
+					}
+					return $fields;
+				}),
+		]);
+		$this->setName("{$name}_proxy_holder");
+	}
+	
+	
+}
+
+class ProxyArrayListField_FieldProxy extends \DatalessField {
+	private static $allowed_actions = [
+		'handleField',
+	];
+	private static $url_handlers = [
+		'' => 'handleField',
+	];
+	protected $originalField;
+	
+	/**
+	 * @param \FormField $originalField
+	 */
+	public function __construct($originalField) {
+		$this->originalField = $originalField;
+		parent::__construct($originalField->getName());
+	}
+	
+	
+	public function handleField(\SS_HTTPRequest $request) {
+		return $this->originalField;
+	}
+	
+	public function Field($properties = []) {
+		return '';
+	}
+	
+	public function FieldHolder($properties = []) {
+		return '';
+	}
+	
+	public function SmallFieldHolder($properties = []) {
+		return '';
+	}
+}
diff --git a/src/Form/UploadField.php b/src/Form/UploadField.php
index 7c1fce9..a0a1e9a 100644
--- a/src/Form/UploadField.php
+++ b/src/Form/UploadField.php
@@ -2,6 +2,7 @@
 
 namespace zauberfisch\SerializedDataObject\Form;
 
+use SS_HTTPRequest;
 use zauberfisch\SerializedDataObject\DataList;
 use zauberfisch\SerializedDataObject\DBField\DataListField;
 
@@ -46,4 +47,45 @@ public function setValue($value, $record = null) {
 		}
 		return parent::setValue($value, $record);
 	}
+	
+	private static $allowed_actions = [
+		'upload',
+	];
+	
+	public function upload(SS_HTTPRequest $request) {
+		$fieldName = $this->getName();
+		$baseStrLength = strpos($fieldName, '[');
+		if ($baseStrLength) {
+			$postVars = $request->postVars();
+			$baseName = substr($fieldName, 0, $baseStrLength);
+			if (isset($postVars[$baseName])) {
+				$postVars[$fieldName] = $this->flattenFilesArray($postVars[$baseName]);
+				$request = new SS_HTTPRequest(
+					$request->httpMethod(),
+					$request->getURL(),
+					$request->getVars(),
+					$postVars
+				);
+			}
+		}
+		$return = parent::upload($request);
+		return $return;
+	}
+	
+	protected function flattenFilesArray($array) {
+		$fieldName = $this->getName();
+		$keys = substr($fieldName, strpos($fieldName, '['));
+		$keys = trim($keys, '[');
+		$keys = trim($keys, ']');
+		$keys = explode('][', $keys);
+		$return = [];
+		foreach (['name', 'type', 'tmp_name', 'error', 'size'] as $field) {
+			$data = $array[$field];
+			foreach ($keys as $key) {
+				$data = $data[$key];
+			}
+			$return[$field] = $data;
+		}
+		return $return;
+	}
 }