As I know, GWT needs that code that will be used on client side to be on the XXX.client package. I also know that is possible to configure this path, allowing other client-side code to be outside this package.
However, I can connect this to solve my problem: I'm writing a library that automate some code I'll be using many times over more than one application. This library has an Exception class that is used in the client-side (RCP methods throws it). How can I inform GWT that this class need to be converted to translatable code?