Calling a stored procedure in an ADFS claims rule
After you have setup your SQL Attribute Claims Store in ADFS. If you want to use it and in fact test it you must set up a claims rule that makes use of it. To do this you must create a claim using a custom rule, which allows you to employ the claims rule language. The following technet entry is a good start as it illustrates how to enter a SQL Query and even a stored procedure.