How do link a Secondary Collection on a form?

I am trying to extend an IDO / Table ("Nonconformances") on a Site level using the 'sa' user.

The Nonconformances IDO was created by Infor at the "Vendor" level, and so the IDO has an AccessAs "BaseQuality" (Infor IQM).

My initial thought was to create an IDO with my additional properties, then add it as a Subcollection to the Nonconformances IDO, but the "New Property" button is grayed out on the IDOs form because of the AccessAs difference.

So, I am attempting to modify the Nonconformances Form by adding my IDO as a Secondary Collection, adding an Edit Control to the form, then Binding the Edit to the desired property in my IDO that way (am I on the right track?)

So far I am able to Add my IDO as a secondary collection, but I am not sure how to link it to the Primary collection.  I've tried editing the "Selection / Permanent Filter Expression" property as: "{primary IDO Property Name} = FP( {Secondary Collection Property Name} )" but this is not working for me.

I am assuming that once I can get them linked, I should be able to Bind my new Edit Control to the right Property of my IDO in the Data Source / Binding Property of the Edit control.

Can someone put me on the right path?

Thank you so much for your help.

Regards,

John Keegan