AX 2012 showing lookup from different (cross) company

I had a requirement in AX 2012 in which I had to show Customer Lookup from a different company. Our requirement was to provide user with two lookups on the Vendor Form (VendTable).

1. One lookup - To select the company from which they want to see Customers
2. Second lookup - Show Customers from the company selected on above lookup

To achieve this I added 2 fields in the table VendTable

1. TargetCompanyId (EDT: SelectableDataAreaId)
2. TargetCustAccount (EDT: CustVendAC) - Don't use CustAccount EDT, I tried this in AX2009 and it appeared to be using EDT relation and could not work.

After adding these fields, create a new relationship and add both of the above added fields in this relationship.

Drop the fields on the form and you will see Customer will appear from the company you have selected in the first lookup. Change company from the first lookup and see how data in the customer lookup changes.