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.

 

If I attribute it directly or add it to the helper class it does not work.

Is this possible?