iCal sych url through Apache

[skenkin]

The URL format below works well if Zimbra is accessed directly by iCal:

http://zimbra.xyz.com/principals/users/username/

What is the format for accessing iCal through an Apache server setup?

Our current format for accessing email the Apache server is:
http://zimbra.xyz.com/zimbra/

The following logical URL format does not work (or any variations)
http://zimbra.xyz.com/zimbra/principals/users/username/

Has anyone gotten this working through an Apache server setup?

Thank you.

[skenkin]

Has anyone tried this at all?

BTW: we are using Zimbra NE version 5.0.6 on OSX Server 10.5.3

Apache version on OSX is 2.2.6