Triggering event whenever PO item added to existing PO

[Shai Eyal]

Hi all,

I have created workflow triggered whenever PO is created with item with
account assignment A. All works well. I try to enhance it such that
whenever an item (with account assignment A) will be added to existing
PO the workflow will be triggered. My question: How can I raise even
whenever PO item (with account assignment A) is added to existing PO ?
As for BUS2012, it's CHANGE, however from change document view it's I
(=Insert)...

I can do it via userexit but I try to avoid it.

Thanks in advance,

Regards,
Shai Eyal