David,
It's great too see when frustration is turned into action. Thanks so much for contributing this.
One simplification: You no longer have to create the service contract implementation and notification type in SQL. You can do it in Tcl, with an 'after-install' callback, which is less verbose and also means that you can use only one version for both PostgreSQL and Oracle.
Take a look at packages/workflow/tcl/install-procs.tcl on the oacs-4-6 branch, in particular the proc 'workflow::install::register_notification_type'. You can setup the callback either in your .info file as in packages/workflow/workflow.info, or through the APM user interface.
I hope you find this simpler.
/Lars
