Problem in copy version of function module

Hi,

I have copied a standard function group V56K to Z, and then copied the desired function module to Z FM. Now I double clicked on the subroutine PERFORM FILL_IDOC_TAB_DELIVERY. It's asking for deveoper key. I guess when we copy to Zfucntion group then should let me change. Cna anyone tell me what si the resolution.

Regards

Rinku