Policy Injection Application Block (PIAB) doesn't have any MEF export attributes on it. There are several easy (although tedious) techniques to get them into the MEF composition container.
1. For each PIAB class, derive a class and apply the [Export] attribute, passing typeof either the interface to export or the PIAB concrete type name. Prism v4 uses this technique in the Prism.MefExtensions component. Once you have all
the type exports in a component, then during bootstrapping add that component via AssemblyCatalog to the MefBootstrapper's AggregateCatalog.
2. If #1 doesn't work because the PIAB class is sealed. You can use a similar technique, but instead of deriving, you export the PIAB class as a property. Glenn Block has a blog post about these MEF "buddy classes". In the get
accessor, you simply return a singleton or new up another instance. You have to make sure to compose the buddy class into the container so that it's exports are available.
3. During the bootstrapping process, you can use the composition container and call ComposeExportedValue repeatedly for each type in PIAB you want in the container. This isn't recommended though as it is harder to debug and static analysis tools won't
be able to see this code.
4. As a last resort, you could apply the MEF export attribute to each of the PIAB classes and recompile the application block.
Gvie #1 a try and let me know what issues you run into.