How to use a stored procedure with my Entity Framework v4 + POCOs

I've got a very simple Entity Framework project with POCO Entities. I've got a single stored procedure which I have imported using the EF Wizard.

I've then made my own EF Entity which I've then Add Function Import to map the Stored Procedure to my EF Entity.

Now, I'm not sure how to map my EF Entity to a POCO. As such, I keep getting the following error:

Error 11007: Entity type 'XXXXX' isnot mapped.

How can I map this entity to a POCO?