Thanks a lot for your answer Matt,
We are looking more about the option 4. We make a test but get an error complaining because “the property CustomerSet does not exist”. Then we tried to add a second navigation property from Phone to Customer, but it give us an error on the Gateway complaining because “PhoneSet is not the main Collection”. It seems than we are missing some configuration. Could you share to us some links or documentation about details about the steps to execute for the options 1 and 4 that you mention above?
Thanks in advance