How Can I Mask a Mapped WPMU Subdomain Page URL?

I’m trying to mask a mapped WPMU subdomain page’s URL.

Here’s a breakdown of what I’m trying to accomplish…

WPMU Primary Domain:

The WPMU subdomain page URL:

Same URL with domain mapping: mapped to (1)


note: should be a parked domain.

Now mask the page URL: (2) masked with


note: should be an add-on domain.


(1) Mapping: use the WPMU Dev Domain Mapping Plugin. Simple…

(2) Masking:

– Use RewriteCond and RewriteRule in’s add-on directory’s httaccess file to rewrite the URL and point it to the directory’s index.php

– Use some sort of masking PHP script in the index.php?

I need help with Step #2 for the masking…