I tested i and it doed get through, so I stand corrected. I have not been able to get anything to execure thus far though

If you use the .Net SQLParamater, it will not allow that value

Another option is to use dynamic SQL in your stored procedure:

--exec UpdateContact 30, 'Joe','Blow',NULL

alter PROCEDURE UpdateContact

@ContactID int

,@FirstName nvarchar(30)

...