I recently purchased a WorkCentre 3615 to replace a 3220. I assumed that the much more expensive machine would at a minimum contain the same utilities and driver features as the dated 3220. After spending a long time on the phone with a tech, he told me that the 3615 does not support PC Fax. He acknowledged the shortcomings and his solution was to reach out to the company that sold me the machine (Amazon.com) for a work around. Unbelievable.
You should be able to send a fax directly from the print driver as follows :
Sending a Fax Using Macintosh Applications
NOTE: You can send a fax from many Macintosh applications by using the fax driver.