Mike,
I think Memory Form here, ie you do all the work yourself, eg, get the File and then p_web.FiletoSessionQueue(File), etc for all the files.
I guess you can hide the normal Save Button, ie only a Close Button on the Form, and add a Button that says Save, where it is p_web.SessionQueueToFile(File) and then a Put(File).
An earlier posting of mine detail the right Embed points when the Form opens, obviously when the Button is pressed the Embed point would be on the Server side.
I have not tried it, obviously, but I think it should work.
Cheers
Charl