Transmission: Adding Trackers

When I try to add a torrent file that already exists, a torrent client like uTorrent will add the trackers from the new torrent. However, Transmission simply gives me the following error:

The transfer cannot be added because it is a duplicate of an already existing transfer.

(Yes, I know that it's a duplicate; I'm just trying to add the trackers.) Is this the intended functionality? How do I add trackers to an existing transfer?