Serializing an entity's field using Entity Framework 4

I've recently been working on a portal using MVC2 and I'm trying to use EF4 as the DAL.

I have an entity called WidgetInstance which serializes it's state into json. EF4 correctly identifies this as a string field but I need this to deserialize to a List<WidgetState开发者_JS百科> when it's loaded and serialize back to a string when saving/updating.

I've googled and SO'd for an hour or so now without much success. I don't really want to create a new DB table for the widget states.

Has anyone attempted to do this before or have any pointers where I can get started with this?

Thanks