The place of Entity framework 4.0 + POCO + WCF in DDD "world"

I'm trying to get to light. In DDD approach we have Presentation Layer(UI), Application Layer(Application Services), Domain Layer and Infrastructure. I'm sure that anyone knows o short description on those 4 layers.

I know WCF feet in Application Layer(Application Services), and the Entity Framework .edmx model in Infrastructure Layer.

Now the "silent enigma" came in: where I have to put POCO objects, the repository interfaces开发者_如何学Python and implementation? I can use POCO objects like Domain Model Objects considering the ignorance persistence of POCO, or is better to have another objects in domain model and map those objects over POCO objects.

I have read some articles but in majority EF4 and POCO are presented in very simple situations where is impossible to highlight the real advantage of using EF4 and POCO, for this I want yours points of view.

Many many thanks!

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POCO can be your domain object because it is persistance ignorant. I don't see any reason to create separate set of objects for persistance and separate set for domain objects. Repository is part of infrastructure layer.