SMT for BP data model for existing ECC field

Hi

Our requirement is  to add Vendor Return check box (KZRET into BP data model.

I added into datamodel for Entity  Type BP_PORG with customer name space as ZzKZRET and assign data element KZRET for that.

Then I activated data model and regerated structure with local package ($TMP) for entity type BP_PORG and for structures SUPPL_BP_PORG_2STA and SUPPL_BP_PORG_2API. Also reconfirm that field ZZKZRET added to above two structures in SE11.

Now want to do SMT so select SUPPL_BP_PORG_2API and mapping step  VMDS_EI_PURCHASING.

When I try to add field mapping 00001 under Transformation tab, it opens as target structure name VMDS_EI_PURCHASING and ZZKZRET is not existing there.Wheare as I found in source structure name MDG_BS_SUPPL_BP_PORG.

Also I reconfirm that Target structur name VMDS_EI_PURCHASING assigned to two sructures

and ZZKZRET exits in both above structures.

What we need to do so that ZZKZRET appears in taget structure name VMDS_EI_PURCHASING?