xpose4 with -99

[JoanaXu]

Hello, it's a new NONMEMer named Joanna.
When I trying to create a plot of ETA vs Covatiates with xpose4.ranpar.vs.cov, I found the covariates with value of -99 was not shown in the plot , which were remain in the dataset(object) with xpose4.xpose.data. So, I wonder if -99 was just handled as missing when ploting in this function? And if the -99 was handled as missing, will the records with -99 will be discarded or only -99 be recognized as NA?
(xpose4 version is 4.6.1)
Looking forward Your comment.

[jn-slp]

I just ran into a similar issue were -99 is used as a placeholder for missing values, but luckily I had the data in another format for reference. The -99 values are actually converted to 99 when the table file is read into R.