Hello,
You can try this.
In WE30, create new extension with copy from another extension.
In attached screen-shot, I'm trying to create a new extension of MATMAS03 using already extended Z-IDoc.
Only problem I can see,In future, if existing extended Z-IDoc is added with new segment.
Your new extended ZMATMS03 IDoc will not be added with new segment. It needs to be added manually.
Regards,
Sameer
