Sorry I thought this was a question about the mysqli login and logout. The clear session (the way you have it) is the way to do it with the security assist login.
Your friends over here at WebAssist! These Dreamweaver extensions will assist you in building unlimited, custom websites.
These out-of-the-box solutions provide you proven, tested applications that can be up and running now. Build a store, a gallery, or a web-based email solution.