Meteor Velocity/Jasmine fails to start Karma through proxy

I am attempting to test a meteor application using Jasmine built on Velocity. When I test the application behind our corporate proxy, Karma does not start, the tests don't run, and I get this error in my Jasmine logs:

stream error Error during WebSocket handshake: Unexpected response code: 301

Presumably because it cannot connect to Karma.

I have tried this outside of our intranet (with no proxy), and it works just fine. Unfortunately, it isn't really feasible to run tests outside of our network.

Is there a setting that I am missing that would make this work?