Entity Framework Error 3002 / 3003 - Inheritance / key mapping issue

I have a data model as follows:

A Customer has Products and Payment Methods. Each Product can be assigned any or all of the Customer's Payment Methods, with one set as default.

Foreign Keys are:

Customer.CustomerId => Product.CustomerId
Customer.CustomerId => PaymentMethod.CustomerId
Product.ProductId => ProductPaymentMethod.ProductId
PaymentMethod.PaymentMethodId => ProductPaymentMethod.PaymentMethodId

I want to customise this model for presentation purposes, Customer to have a collection of Payment Methods and a collection of Products. Products to have a collection of ProductPaymentMethods which inherit from PaymentMethod.

I deleted the association between PaymentMethod and ProductPaymentMethod, added an inheritence from PaymentMethod to ProductPaymentMethod and deleted PaymentMethodId from ProductPaymentMethod.

This is now my model:

When I save the model or build the project I get 2 errors:

Error 3002: Problem in mapping fragments starting at line 226:Potential runtime violation of table ProductPaymentMethod's keys (ProductPaymentMethod.ProductPaymentMethodId): Columns (ProductPaymentMethod.ProductPaymentMethodId) are mapped to EntitySet PaymentMethods's properties (PaymentMethods.ProductPaymentMethodId) on the conceptual side but they do not form the EntitySet's key properties (PaymentMethods.PaymentMethodId).

and

Error 3003: Problem in mapping fragments starting at line 226:All the key properties (PaymentMethods.PaymentMethodId) of the EntitySet PaymentMethods must be mapped to all the key properties (ProductPaymentMethod.ProductPaymentMethodId) of table ProductPaymentM开发者_JS百科ethod.

What am I doing wrong?

EDIT: Having done some further Googling, I have found several solutions, most of which don't quite fit this scenario. Most talk about inheritance requiring a 1-1 not 1-many relationship. However, because of the Customer to Product 1-many relationship, the model requires a 1-many between PaymentMethod and ProfilePaymentMethod. Is it not possible to do what I am attempting?

My only answer to this so far is to have some manually created POCO classes for presentation and a Mapper class to turn my data entity into a presentation entity