Customizing AX7 data entity

Hi,

I'm trying to customize AX7 CustCustomerEntity to add with a new table and field, however I can't seem to be able to do what I want to do.

Background:

I created an extension model and add a master table, say it's called PermitTypeTable.

Then I extended the CustTable to add the PermitTypeId field (RefRecId type) and put a relation into the PermitTypeTable.

All is well at this point.

Then I want to add that PermitTypeId into the CustCustomerEntity. As per my understanding AX7 does not support data entity extension yet, and so I created an overlay model and I selected the ApplicationSuite package because the CustCustomerEntity belongs to the ApplicationSuite model.

Now the problem is, I can't add the PermitTypeTable (belong to the extension model above) into the CustCustomerEntity, and I can't add the reference of the extension model either because that model doesn't appear in the selection at all.

I have tried to rebuild everything, but it doesn't seem to change a thing.

Am I missing something here?