Well, I've got 50+ hits but no replies so I'll post what I've found out so far in case it can help someone in the future:
http://docs.info.apple.com/article.html?artnum=301077
From Apple - shows you how to set up a bluetooth modem for faxing from your cell phone. It is not, however, supported by apple techs.
Even after following these steps, I can not use my BB8100 as a fax modem. Getting errors (fax protcol) that I'm trying to fix now.