How do I configure MeCanto to connect through my Proxy at work?

Edit Subject

When I attempt to connect to the MeCanto servers, it just hangs, trying to connect forever. I've had issues with other applications in the past that have no proxy setup option available.

One answer given by MeCanto what that if you can get on the Internet you will have no problems, but I cannot get on the Internet where I work unless I enter my username and password in to the proxy pop-up window first. I think MeCanto is having the same problem, no way to enter proxy login info.