Redirect with the server name INCLUDED as a parameter.

Hello,

I need to redirect a URL to another one... and pass the complete URL as a parameter.

For example, if I type this URL:
http://host.domain1.com/Test

I have set "A redirection to a URL" with this value:
http://host.domain2.com/Dir/SubDir/Appl?RedirectTo=$V

The URL shown is now:
http://host.domain2.com/Dir/SubDir/Appl?RedirectTo=/Test

I'd like to have this after my RedirectTo param:
http://host.domain1.com/Test and not just /Test (because as you can see, I'm using two different domain names).
In other words, I'd like to have this:
http://host.domain2.com/Dir/SubDir/Appl?RedirectTo=http://host.domain1.com/Test

I looked at $S, $P, $Q, $V... but none of them add the server name.

Is this possible?
If so, how could I achieve that?

Thanks a lot!
Pascal