Print to fax from application with faxnumber as parameter...

I am not as experience with Windows Fax, except as a user on Windows 7. Now I need to implement a fax server on Windows 2008 R2 with Windows 7 clients. No big issues with that.

The remaining quoestion is related to printing from an application to windows fax. We would like to automate this without the Fax Client popping up asking for Faxnumber and and additional information. That is, the application would send all necessary information like faxnumber and any other needed parameters together with the document to be faxed. 

Yet, I seem not to be able to find a documentation about how the application actually has to send that information to the faxprinter. Can anyone point me to such a documentation?

I remember that in earlier times (that was years ago on UNIX), the application had to add this information into the header of the file sent to the fax service.... How's that done with Windows Fax?

Thanks a lot

Dan