Windows Auth in Firefox with Backslash

Hi all, I am using the code structure below and the page load times out. If I remove the escaped \ in the username, the page loads by throwing the expected 401 Unauthorized.

Is this the right way to pass the credentials to the Win Auth, and is it the \ that is actually causing the problem?

WebUI.openBrowser(’’)

WebUI.authenticate(‘http://tocbhpqc1uv/Streamline’, ‘Domain\\username’, ‘password’, 12)

Thanks