To support switching the language when a program is up and running, the Add-In can add the MLRuntime project to your solution. The purpose of this project is to fire an event when the language is changed, which can be handled in all active components.
The point of making it a separate project, is so that the events can work across separately compiled components. (If you don't need this ability, then you could copy the MLRuntime class directly into your own project).
The Add-In already has 4 separate templates for VB and C# with VS 2005 or 2008. Unfortunately, none of these will work correctly for a smart device project, because they do not target the compact framework.
I will be fixing this in a future version, but in the meantime, if you hit this problem, then the easist workaround is to create the MLRuntime peoject yourself. All you need to do, is to create a Smart-Device project, with the project type Class-Library, and to copy the MLRuntime class (in VB or C#) from one of the template projects. After that you add a reference to from your original project.
8th April 2008