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.]
I recently updated the website on which the above blog is hosted, and the correct URL for the above SSTP/SBS08 article now ends with .aspx and not .shtml. Therefore see http://www.c7solutions.com/blog/2008/06/sstp-ssl-vpn-on-sbs-2008-rc0.aspx. I will update this in the new year for the RTM version SBS 2008.
C7 Solutions Ltd