I have a client who currently sends "email-to-fax" through the fax services
of SBS 2003/exchange using the  [fax:5551212] addressing format.  Seems to
work great for them, but several of the users have been going offsite and
using Outlook Web access to transact their email.  Unfortunately it seems
that they are not able to send faxes through OWA in the same manner as they
are used to with the full Outlook client.  

Is there any way of setting this up to work from OWA?

Cheers,