Just for my own record because I always forget:
If you ever need to pass any object data to a custom control, use this as the property data type:
com.ibm.jscript.std.ObjectObject
or
com.ibm.jscript.std.ArrayObject
depending on if you just need one or more objects.
This is a companion discussion topic for the original entry at https://oliverbusse.notesx.net/hp.nsf/blogpost.xsp?documentId=24AE