As you know SSTP support in Windows Server 2008 allows you to configure RRAS server role as SSL based L3 VPN server - which allows VPN clients (currently Vista SP1, WS08 and later releases) to connect from anywhere - behind firewalls/NAT.
If you would like to run Small business server (SBS) on top of WS08 server and will like to use SSTP functionality, here is a good blog which gives you the exact steps required to achieve the same
(Special thanks to Yuta Kawamoto for pointing me out of this issue and Brian Reid @ C7 solutions to document the steps out)
Sr. Program Manager
Windows Networking Group
[This posting is provided "AS IS" with no warranties, and confers no rights.]