As you mentioned, it is not actually about .resources files, it is about embedded resources within a certain assembly, known as satellite assemblies.
Quote:Beginning with the .NET Framework 4, the AssemblyResolve event is raised for satellite assemblies.
You will need to return the assembly containing the resource
A .NET Framework assembly containing resources specific to a given language. Using satellite assemblies, you can place the resources for different languages in different assemblies, and the correct assembly is loaded into memory only if the user elects to view the application in that language.
, as this short sentence tells you:
Quote:The ResolveEventHandler for this event can attempt to locate the assembly containing the resource and return it.
Hopes this help.