Long time ago I tried it...but gave up... this plug works when the path and the name is typed in (partly, because sometimes even if typed in it refuses to load/save to a different file than the one first selected).
Someone should write the plug again (Please GS) from scratch so this functionality worked (that's why eg. Cadimage did for themselves as they use a lot of ways of saving things in their objects).
Best Regards,
Piotr