Is it possible to add E1EDKA3 under E1EDKA1 in Extended IDOC ZINVOIC02?

Dear All,

I need to add E1EDKA3 under E1EDKA1  in extended idoc ZINVOIC02.

Is it possible ? when i try to add i got below error:

Name range violation : Name E1EDK03 not per in CUSTOMER system

Is this possible in standard? if possible please explain me?

Or i need to and created ZE1EDKA3  segment and add under 1EDKA1  in extended idoc ZINVOIC02.

Kindly help me...