Idea hangs up accessing svn through proxy

I'm trying to get Idea 5.1.1 to connect via https to an external repository. I have to go through a corporate proxy, although I don't have to authenticate with the proxy. Idea is running on Mac OS X 10.4.6.

I've set up the .subversion/servers config file properly to support my proxy, and I can fully access the repository via svn on the command line. Checkout and commit both work fine on the command line.

But Idea never finishes the initial server connection when I try to browse the repository, or if I try to commit from a working copy created via the command line tool. I get the "connecting to ..." progress dialog, but then it just sits there. I've let it go as long as 5 minutes before force-quitting Idea.

Any suggestions on what this could be, or how to debug it? I gather that any exceptions should show up in the Console app, but I haven't seen anything. Is there anything I can do to force Idea to be more verbose in it's logging?

Thanks,
Willis Morse