add a table for your incremental numbers. Calling a script to create new serial number in the number table and return it to the original table when execution is desired. ??
I don't know if this script step will help as it requires an auto-enter serial
but perhaps with fclark's suggestion? Please specify if this is multi-user, as methods may fail to grab a "next" serial may give unpredictable results.
Thanks. I was hoping for a more direct solution, but yours worked like a charm.