Setting distinct map download server

[Ironwall]

Is there a way to have pk3 files autodownload from a different server than the one hosting the game? I set up a gameserver on my computer which works perfectly, except maps download too slowly to be useful. I have access to webspace that can handle a very large load, and should therefore make map downloading a snap, but I don't see any way to redirect downloads to another source. It's not really a security concern because you're already blindly trusting the host computer's files.

[fufinha]

sv_dlURL "http://etc"