Define field restriction for Event

[Kobi Sasson]

Hello

I needs some help.
I defined new business object subtype for vbap called zvbap
then I created new Event for qty order in sales document item data (KWMENG)

but when i tried to define the field restriction with the wizard SWU_EWCD
I selected the object type zvbap and select my event when I tried to
continue
I get message "No Change document object for business object type zvbap"

Please Can some one help with tis issue.

Thanks.