WordPress MU

We are trying to share a single host name, sharing it between another webapp and with wordpress. The environment is:

Apache 1
Has a virtual host entry for site1.cxm
Includes a proxy pass for site1.cxm/path to go to site2.cxm
All other traffic goes to another app that we want the end
user to see as the same basic url (minus the extra path)

Apache 2
Has a virtual host entry for site2.cxm
Running with php
Has wordpress-mu on it

Issues:

Apache 2 (wordpress mu on it)
When telling wordpress mu that its site url is site2.cxm, all of the links that are built are for site2.cxm but we want them to be site1. That said, the pages do load but the URLs on the pages are not what we want.

When telling wordpress mu that its site url is site1.cxm, somewhere in wordpress-mu it seems like it sends a 301 back to the browser saying its moved to site2.cxm (its like it detects that is host name != site url) resulting in an endless loop 301.

Has anyone tried to do this - share a host name between two apps (one app being wordpress-mu) with the path in play being the splitting logic?

"When telling wordpress mu that its site url is site2.cxm, all of the links that are built are for site2.cxm but we want them to be site1."

You can't. MU stores the actual domain in too many places in the db.

you can look into some domain mapping plugins to try and fudge this, but I can;t see it working (or why you'd want to)