How did you create the discount? Can I see a screen grab of the discount rule you have set up? You probably just have to use TotalPrice instead of Price when calculating.
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.