Is there any way to write to the Message Log panel from a transform script?
If you want to debug some script use Debug java script dialog in Custom transformation scripts dialog. Or try Kris' variant
Kris' blog: Modeler Custom Transformations
Thankyou for the answer, it works wonderfully, sort of.
The only problem (which is nothing I think you can do much about) is that the display doesn't update until after the script finishes.
Not a real problem, just an unexpected side effect.