I can't find any documentation on how your Single-Sign-On service works exactly.
I would like to try and judge wether it is suitable for our site.
Something like http://www.userrules.com/developers/single-sign-on-how-to would work.
After registration you can browse SSO docs here.
http://[your project alias].userecho.com/settings/features/sso/
Also we make it accessible without registration soon.
Look at screenshot below.