Editing a DLL's App.Config File from an EXE

Question

I have a DLL project in VB.Net which has an App.Config file for settings but I also need to be able to open an EXE from the Start Menu in order to edit the same settings.

If I create a project from the EXE, how can I bind the app.config to the DLL project? I've tried a number of things, including putting the EXE in the same solution as the DLL project. No joy though.

Thanks!