In Environment parameter settings you can use APPROVALSTATUSMAIL together with APPROVALSTATUSMSG. You can read more about this at http://help.sap.com/saphelp_bpc10_ms/helpdata/en/4c/87848933401cf2e10000000a42189b/content.htm?frameset=/en/a7/81a5d88e2445019dbbd592ff516299/frameset.htm¤t_toc=/en/b8/5eaf1e32a941738a7a4df31ec32be8/plain.htm&node_id=83
This function will trigger a e-mail if there is a change to the work status and not only between for example unlocked to submitted.
Brgds
Mattias