SSO between DWA and ST

will SSO work between domino web servers configured 1st one as Internet site and 2nd one web config (server doc) ?I have several servers confiured as SSO and all works fine as long as these are configured via Internet Site docs, on the other hand I have Sametime Server configured via server doc (as far as I know Internet site should not be used for ST Server)

can this be done? I get “HTTP Server: Error loading Web SSO Configuration ‘LtpaToken’ (Single Sign-On configuration is invalid)” on Sametime server ONLY

Tim