Get item_number of Change Item in PE_ChangeItemTransition

Hi Community,

does anybody know how to get the current Change Process item (basically it´s item_number, like ECO-10001) within the PE_ChangeItemTransition Method?

I want to modify the private static void PromoteImpl part around line 5297. 
This part of the code takes care for the promotion of the change item.

It contains this line of code:

Item res = promoteItem.promote(nextStatus, "Promote set");

I want to add more information to the history entry that is created by this promotion action. It would be cool if Innovator could write more into the history than just "Promote set". It would be more helpful if we could have "Promote set by ECO-10001". But for this purpose we need to pass the ECO information to the function. But I am not sure were to get this one.

Any ideas?