I have a table where I created an INSTEAD OF trigger to enforce some business rules.
The issue is that when I insert data into this table, SCOPE_I
Since you're on SQL 2008, I would highly recommend using the OUTPUT clause instead of one of the custom identity functions. SCOPE_IDENTITY currently has some issues with parallel queries that cause me to recommend against it entirely. @@Identity does not, but it's still not as explicit, and as flexible, as OUTPUT. Plus OUTPUT handles multi-row inserts. Have a look at the BOL article which has some great examples.