[Zope] Invalid Characters for a URL?

I'm porting some data to a Zope environment, and it is critical that URL's remain the same. However, Zope does not allow plus signs (+) in URL's. It tries to pass it off that plus is an invalid character for a URL. However, plus is a perfectly valid character for a URL (ref: http://www.ietf.org/rfc/rfc1738.txt). So, why is Zope doing this, and much more importantly what does Zope think ARE valid characters for a URL? --- Edward J. Pollard University of Lethbridge Web Development