I don't believe that's a feature of PDFG, I have seen it done with LiveCycle Data Services (LCDS) however.
Even we are trying to convert SWF file to PDF file and it is not working out. I believe that we should have Acrobat 9.0 or higher in order to use Generate PDF service. We have Adobe Reader version 9.3.1.
I believe you can convert a swf movie, but not a swf form.
What error are you getting