I have the same question and I have been researching for quite some time now. The only thing I could find was that u install ssh in your ipad through cydia. Then u install Cyberduck on your mac for windows it is winschp I think and then you can connect into your ipad's directory.
After that go to /private/var/mobile/Documents/Installous/Downloads and there all the ipa files are there. Copy them and store them on your Mac or PC.
Have Appsynch 3.2 installed on your ipad through cydia and then drag and drop these ipa files in your app diretory in itunes.
I still have to try the last part will do that today and update.
Unless there is something easy out there.