实体框架4仅代码错误“不支持每种类型的多个对象集”

I have two "Code Only" POCO's using EF4 and the latest CTP, running against an existing, legacy database. Running a LINQ query against PocoA worked until I added the property below to that object, I was trying to add a relationship.I have two "Code Only" POCO's using EF4 and the