Customize Outlook Web Access for multiple virtual sites

Hello,

I work at a county office of education and we host email for many of our school districts. We are in the process of moving from 2003 to 2007 and as part of this transition I would like to customize the way OWA and the initial log in screen looks to include school colors, logo, etc... I understand that the users on the 2003 servers will not see the OWA changes and that is alright.  They will still see the new login screen.

I have found a couple of great documents on doing this

http://msexchangeteam.com/archive/2006/08/30/428793.aspx
http://technet.microsoft.com/en-us/library/bb310750.aspx

but what I can not find is how to do it on a per virtual site bases. 

We are setting up a virtual server for each district in order to default their domain name in (so that they do not have to enter it at login).  My first thought was to create a theme specific to each district and then set it using

Set-OwaVirtualDirectory -DefaultTheme

This sounds like it will work great but does not cover the login page. So I wondered if I could make a copy of the login pages (one for each district), customize those and then point each virtual site to its own login screens.

Is the above the only way to do this?  Will it even work?  Is there a better way?


Thanks in advance for any help or insight you can provide.

James