You probably saved the template with the default file extension Sonar adds when saving a project, that of a CWP extension, and these do not show up as templates, because they are actually projects.
If what you are happy with on your screen for a new template, do the File>Save As, give it the name you want, but also change the File Type to Template, and navigate to the Sonar Version-specific Project Templates folder, and THEN hit Save. This will ensure that it gets saved with the CWT extension, which are the only ones displayed when you get the list of project 'types' when creating a New project.
Hope that helps,
Bob Bone