Question

I have a proxy entity but I want to save the poco entity to the session

Answer 1

First, have you got your solution setup for generated POCO objects? If not, you should read this MSDN article and this article on using the POCO Generator

Once you have, make sure you turn of the use of proxies when you use a DataContext. Can you provide more information about your solution?

Example of disabling Proxy Generation:

// Disable proxy object creation.
context.ContextOptions.ProxyCreationEnabled = false;