The CreateTableSignal class is accessible via the sqlobject.events module.
Called with (cls, connection, extra_sql, post_funcs). extra_sql is a list (which can be appended to) of extra SQL statements to be run after the table is created. post_funcs functions are called with (cls, connection) after the table has been created. Those functions are not called simply when constructing the SQL.
See the source for more information.