It was pretty trivial to do.
1. Generate a server cert request from Windows on your server
2. Have your CA sign it, and then install it on your server.
3. Use the MMC to copy the server cert from the Computer Store to the Service store (I think)
4. Make sure to edit sbhttp.ini correctly...and SAVE a copy elsewhere, since every upgrade OVERWRITES this file.
(IRRITATING!!!!--just like overwriting the backup license file)