[Zope] uploading to Zope with Mac Browser

Zope list: This zope method for uploading images to server: <dtml-call expr="manage_addImage( id=title, file=file, title=title)"> ...works great from a PC. But from a Mac (netscape And IE) it does not work. Sometime a file is uploaded, but it is garbage. Apparently the Mac browsers have a totally different way of packaging data from an <input type=file> element. Does anyone on this list know how to deal with this? Is there a Zope product? Thanks in advance for any help with this fundamental problem using Zope. Richard