problems:
>1. don't know how to change fonts of the messages (not really important for e-mail but sucks if you can't do that for a fax).
>2. cannot send without a message. Makes sense that it works this way because what is there to send if you don't have a message. When you're faxing you may just want to send an attachment rather than a message. Any message you send goes on a brand new page. I don't know if there's a way to stick the message on the cover page to spare the recipient from a page with virtually nothing on it.

Avalaible solutions:
Do not use mapi controls. If you have Office installed, you can use 'Microsoft outlook' to create an object and then manage it like an activex object. Doing this, you can create a word document as the message (or fax) and attach it to the message without body nor subject. You can change fonts, size, bold font etc in word document via ole automation.
This is what i'm using now, and it works fine. The only thing i still can't do is to tell outlook exactly which is the direction of my contacts folder, but you can tell him the fax number or the e-mail direction.
About winfax, sdk works fine too. In a few days i'll put in the files section of the UT documentation and samples about it i've downloaded.
Hope this helps.
Carlos.