I thought this would be straightforward, but it wasn't.
I'd like to modify the standard script for CREATE TABLE. (DB is PostgreSQL 11.) I have two scripts in My Package. In each I copied one function from PERCodeGeneratorPG, once the Internal Script version, once the JScript. Neither is being called when I generate DDL (I can tell because they should output a comment string, setting aside the added logic.)
My guess is I missed one step telling it to override.