Do the SVN server Trac relates to have to reside on the same as the Trac installation?
At present, alas it seems so. (If you’re new to Trac and need a one-stop-shop of commands, look here.)
http://trac.edgewall.org/ticket/2828 points to and abstracts http://trac.edgewall.org/ticket/493
Seems like Trac and remote SVN is not happening yet, though SVN replication is an option… There is also an obscure comment some two years ago about a remote plugin, which was at alpha, but the project seems to have since disappeared/moved…
Sigh…