Windows Fax

If theres a shared fax on SBS server, how is Windows XP Fax in play here?
Windows 7 has “windows scan and fax” feature which can make this work.

In XP, Ive added this shared fax as my local printer, added fax feature from add/rem programs, launched fax console but all my test faxes are still in outbox and could not be sent.

Any thoughts? Thanks!