I just sent a test fax to my office unified messaging inbox and the sipgate Faxprinter worked like charm. The transmission of the 2-page file took about 5 seconds. Soon after I received a protocol e-mail and then the fax itself.

It's a bit strange that this comes as an application instead of a permanent printer driver, that's probably due to the fact that you have to be registered and logged in with sipgate to use it. But since I only seldomly have to fax something, that's fine with me.