There are many ways to trigger event for a workflow to start from (changes documents for example). use might event want to check transaction swel to see if an event is created anyhow when an article is crated.
but if you want specifically IDOC event creation maybe this will help:
https://help.sap.com/saphelp_erp2004/helpdata/en/78/2177a251ce11d189570000e829fbbd/frameset.htm