While we have successfully integrated with various SSO solutions, no two are precisely the same and there is no easy formula. However, if you contact consulting they will be happy to step you through the steps necessary for your circumstances. Roughly, MediaBin provides a trusted mode than can be turned on to specify that authentication has been accomplished by an outside entity.Cheers,Lyman Hurd
It is unlikely from your explanation, that a Windows based authentication mechanism would work for you, since you imply you want to allow users to connect to MediaBin that are not part of your Active Directory. As Lyman mentioned, SiteMinder or some other third party authentication tool would be a solution. We have customers that are successfully using SiteMinder. I'm not familiar with the details, but I know they have customized default.asp to meet their needs.
Please try contacting Interwoven Support or Interwoven Consulting Services as they would have more expertise in integrating with third party authentication tools.