When the logs are displayed the URL is constructed using the make_log_url() function in course/lib.php. Unfortunately the module names are hard-coded in this function. This makes it impossible to add functionality for a plugin. The default activity for an unknown module name is to modify the URL with /mod/$module on the front which is only what you want in limited circumstances. The workaround is to pick a module type that does not munge the URL which means the log report is going to be less useful than it might have been.