a question on how to customize interface

hi,

i would like to make a copy of DATA: gd_ref_to_menue01 TYPE REF TO IF_EX_FI_ITEMS_MENUE01.

to DATA: gd_ref_to_menue01 TYPE REF TO ZIF_EX_FI_ITEMS_MENUE01 by changing its parameters "it_items" associated type to a z-type(i have create the z structure in the system). Ss it possible to do so?

if yes please advise the step to do that.

Thank you.