In SiteMinder R12.8.8 and below only supports adding user attributes in the claims.
This has been improved in R12.9 where you can select between the "UserAttribute" and "Static".
This article provides idea on how to workaround this on the R12.8.8
SiteMinder R12.8.8.01
In the following sample AD User Directory Definition (IDP1-AD-Sample-Userstore) set the following virtual attribute named "static-test".
This "static-test" virtual attribute is set as below.
So if there is a query for this "static-test" attribute for the "IDP1-AD-Sample-Userstore" userstore then the value returned will be "test".
Now apply this in the Authorization Provider Claims Mapping.
Then test.
OIDC_CLAIM_test has the static value "test".
If this workaround does not work then upgrade to R12.9 to make use of new feature which allows adding static values in the claims.