Although most function strings are executed in replicate databases, you execute the create function string class command in a Replication Server, usually a primary Replication Server, that has routes to all sites where the function-string class is to be used.
This command designates that Replication Server as the primary site for the class. Function-string classes are replicated via routes, along with other replication system data.
You can only create or alter function strings that have class scope at the primary site for a class. Function strings with replication-definition scope must be created or altered at the primary site for the replication definition.
create function string class rs_sqlserver_function_class
After you have executed this command, you can use the move primary command to make further changes to the primary site for the function-string class.