Summary

As previously described in General Discussion https://ephere.com/plugins/autodesk/max/ornatrix/forums/general/thread_12887.html

I cannot open the Expression Editor of the Generate Guide Data Modifier even in 3dsMAX 2017 (19.0 SP3)
I also cannot open it in MAX 2014.. but then the documenation already states as much.

I only really need to know the variable name for the previously generated Guide Data so I can multiply it with texture map values. The Expression Editor would be very helpful in this.