Module import and use in GHC plugin?

In writing GHC plugins, how can I (a) add a module import (preferably qualified) and (b) make vars/ids for names imported from the newly imported module (to insert in the transformed Core code)? If it's not possible to do what I want, I'd be willing to require an explicit import (say "import qualified Foo") in client code, as a temporary workaround. So far I've been unable to import even from the base package. Maybe I'm missing something basic that you folks have learned. My simple & unsuccessful attempt is at https://github.com/conal/plugin-import-id . Help greatly appreciated. Thanks, - Conal