Addin using GAC referenced assembly

I've got an addin that is also loaded from an IWizard template. The assembly containing the implementation of IWizard and the addin itself (implementing the Connect method) is installed in the Global Assembly Cache. However, although the addin can be launched from a vstemplate file in the template using a full assembly reference, I cannot launch it from the '.addin' file.

Is it possible to reference assemblies from the GAC in a '.addin' file because the documentation only describes referencing assemblies from the local path or from a URL