[Plugin: WordPress MU Domain Mapping] Domain mapping redirects : Correct behaviour?

Hello,
I have created a WPMU site with DNS wildcard domains. I’m using LDAP and newly authenticated accounts have a new blog created. Unfortunately the username is not very pretty and the resulting URL http://abcde00.domain.com does not reflect the use of the blog. We’re using Domain Mapping to remedy this.

2 issues:

The problem is that if we use the new domain as the Primary the web site gets stuck in a redirect loop.

If we use the username domain as the Primary the well named URL redirects to the old/unwanted URL.

Is this the correct behaviour?

This is the URL Rewrite code:

<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
#RewriteRule ^index\.php$ - [L]

# uploaded files
RewriteRule ^([_0-9a-zA-Z-]+/)?files/(.+) wp-includes/ms-files.php?file=$2 [L]

RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^(.+)$ /index.php/$1 [L,QSA]

# add a trailing slash to /wp-admin
RewriteRule ^([_0-9a-zA-Z-]+/)?wp-admin$ $1wp-admin/ [R=301,L]

RewriteCond %{REQUEST_FILENAME} -f [OR]
RewriteCond %{REQUEST_FILENAME} -d
RewriteRule ^ - [L]
RewriteRule  ^([_0-9a-zA-Z-]+/)?(wp-(content|admin|includes).*) $2 [L]
RewriteRule  ^([_0-9a-zA-Z-]+/)?(.*\.php)$ $2 [L]
RewriteRule . index.php [L]
</IfModule>

Thanks for any help.

Owen.