You can add a DataEntityProperty for these "non-native" properties.
It looks like we don't have this documented, but you can "extend" the PropertyMetadata partial class for the entity to add the static DataEntityProperty field. Something like this:
public partial class Customer {
public string ACustomProp { get; set; }
public partial class PropertyMetadata {
public static readonly DataEntityProperty<Customer, string> ACustomProp =
new DataEntityProperty<Customer, string>(propertyName: "ACustomProp",
isNullable: false,
isPartOfKey: false,
concurrencyStrategy: ConcurrencyStrategy.None,
isAutoIncrementing: false,
relatedNavigationPropertyName: null,
isNativeProperty: false);
}
}
DevForce will discover the property definitions when the model is accessed. You can then obtain property metadata from the EntityMetdataStore.