In V8 select Company|Preferences|Form Settings (from the main menu).
Then select the printer to use for Faxing.
However, note that all the fax card is doing here is intercepting the print request. It's a crude and basic interface suitable for sending out the occasional fax, but not of much use for bulk faxing of statements, etc.
There are ways and means of setting up bulk fax but I would not suggest attempting it with a fax card/printer interface approach. However, because faxing is not so popular anymore the above may be all you might need.