Network domain in image urls, how to change to mapped domain instead

Is there a filter to use the mapped domain in image URLs rather than the network domain and sub-folder?

The rewrite rules are working perfectly…

So an image stored in the network domain http://bozemandigital.com/mt4x4/wp-content/uploads/sites/4/2011/09/mountaineers_top_truck_2011_053.jpg

Can be accessed via the mapped domain http://mt4x4.com/wp-content/uploads/sites/4/2011/09/mountaineers_top_truck_2011_053.jpg

The first (network domain URL) of the two examples is what is showing up in the admin media area as the image URL. I’d like it to show as the second (mapped domain URL).

Also, when viewing page source, the first URL (network domain) shows up. I’d like the second (mapped domain) to be used.

I’m hoping that someone can advise me how to set up a filter in functions.php to make this change…as it is a bit over my head.

Thanks!

http://wordpress.org/extend/plugins/wordpress-mu-domain-mapping/