Edit the rs_create_test_db_repdef.sql script in the $SYBASE/RAX-15_1/scripts/sybase directory so that all occurrences of {pds}.{pdb} contain the name of the Replication Server connection used by your Replication Agent. Then, use isql or another query processor to log in to the primary Replication Server and execute the rs_create_test_db_repdef.sql script to create a test replication definition.
