[Zope] File Uploads and SSL

HI all, I'm having a very strange problem, and I hope at someone else has had this happen to them ;) When using SSL and Zope (versions ranging from 2.3.1 to 2.3.3), I have a form that allows upload of a document. The problem is that files over 11-12k in size never finish. If I take SSL out of the equation then files of arbitrary size upload and finish with no problem. I've tried this with M2Crypto and Apache mod_ssl and both suffer from the same problem. I have no real idea what's going on here, anyone else have any ideas? tia Phil