I want to relocate the Flash player plugin of Firefox cache so that it saves my C: drive space when I watch youtube videos. I successfully changed the firefox cache by opening about:config and then created a new string key "browser.cache.disk.parent_directory" where I put the value of the new cache location. But it doesn't work with online streaming contents such as youtube videos.

Please guide me where does it get stored and how to change its cache into another drive.