There is a path and filename command in Acrobat for the currently loaded document. To get at the doc object you can use the event.target command. So to get the filename use event.target.documentFilename and to get the path use event.target.path. Remember to do this after the file is saved.
Let me know that it worked for you.
thanks for the help. event.target.path works. I call it postSave in a textField like this:
this.rawValue = event.target.path;
The result is for instance "/D/temp/Test1.pdf". So with some corrections (cut the first slash, paste ":" behind the "D") it looks fine for our needs.
With event.target.documentFilename the result is "Empty".