I have already written about UAG authentication providers available out-of-the-box ( here ) and mentioned " WinHTTP " and " Other " options as the way to extend this default functionality. Here's a good example based on a popular configuration for exposing Sharepoint based content to external parties (extranet): UAG + SQL Authentication + Sharepoint FBA . This would basically be a 2 part process, and I found a couple of great blog posts that cover it really well: Configure UAG for SQL authentication ( http://bit.ly/L1Gizs ): Define custom authentication provider in UAG (for the SQL/aspnetdb) Add a custom [repository].inc Build a custom authentication function (within [repository].inc) Enable UAG SSO ( http://bit.ly/MYrgZQ ): Extend the Sharepoint site to external Users using ASP.Net Membership Publish the extranet Sharepoint site via the UAG Configure the UAG to work with Sharepoint FBA Many thanks to Andreas Hecker for putting together t