[Zope] WebDAV filesystem access

Hello, I noticed that when you're going to Zope via WebDAV, the files are presented as "rendered", i.e., as they would appear via HTTP. DTML tags are interpreted, for example. What am I missing? This seems pretty worthless. How can you maintain a web site with a WebDAV filesystem, if you can't edit the 'source' DTML pages? Thanks, Derek