I don't know how visual stuido handels exported templates, but i know from modifing the default templates that visual studio has two versions of a template. One you will find in the "ProjectTemplate" folder the other will be in "ProjectTemplateCache".
Maybe your exported template is still inside the cach without your modifications. Try to refresh the cache by statring visual studio from cmd using the parameter: "devenv /installvstemplates" or "devenv /setup".
If you want to create more than one template, I recommend to download the Visual Studio and use a VSIX project to depoly the templates. The SDK also allow to debug the templates in a much more efficent way. You can press Debug and you will recive a Visual Studio instance with a installation of your VSIX (your templates).