Here I have for all to refer Integration document for ARS 7.6.04 SP3 with Atrium SSO 8.1& SAMLV2.
May be some of the steps wont work for you, as I have prepared this document what I followed to make this integration working.
Product Versions (All installed on Windows 2008 R2):
ARS 7.6.04 SP3
Atrium SSO 8.1 & SAMLV2
Both Atrium SSO and MidTier configured on the same machine.
In the attached document I have included all the reference documents which I referred, just to make this document more helpful.
Feel free to share your feedback.