Purchase order creation - event?

[Sheth, Neeraja]

In SAP 4.6C, we need to have a release strategy for purchase orders. If certain conditions are met, the purchase order should be released in the background by a workflow, else a work item appears in the approver's inbox. One event that triggers the workflow is bus2012.changed.
 
I also need to trigger the workflow when a PO is created. Output determination did not help in this scenario - the triggering event could not be created as an output as long as the PO was unreleased.
 
Any ideas would be helpful.
 
Regards
 
Neeraja
X4332