[Zope] How to upgrade Python in older Zope?

Folks, I desperately need support for large filesystem so the data.fs file can exceed 2 GB. I can only make minimal changes to the existing set-up, which consists of Zope 2.5.1 (binary release, with Python 2.1.3) on Windows Server 2003 and NTFS. From what I've read, the issue is with the old Python not having LFS enabled, so I thought I'd just upgrade it to 2.2.3 which has LFS enabled. The question is, how do I do that? Windows installer for Python doesn't know what to upgrade in the Zope install, so I'm thinking to copy the right files from the extracted Python 2.2.3 in Zope folders. What goes where? I appreciate your patience and spoonfeeding. :-) Thanks in advance! Titel