SAP MDG Custom- Data Model Issue

Hello Experts,

I am trying to establish a custom data model for cost center and controlling area, and I have created one type 1 entitytype and assign some attributes in it as key fields those are coming correctly in UI,

but there is one entry for cost center If I am giving it in attribute it is showing me the below error :-

hence I have added that as type-3 entity and gave the referencing relationship to my type-1 and data model is activated correctly, but the problem is I am not able to see my cost center field in my UI.

Could anyone please provide any inputs.

Regards

Ashu