Microsoft have updated their Surface 2.0 SDK and runtime bits to include improved support for Windows Touch Enabled devices.
This is what Microsoft said about the update:
There were some issues in the Microsoft Surface Input Stack handling of reports sent by a digitizer in serial mode. These issues caused the input stack to not report all touches reported by the digitizer reliably. The new build handles input from serial and parallel/hybrid digitizer more robustly.
We encourage you to use this update, especially if you are building applications that will run on Windows 7 touch enabled PCs. With the Microsoft® Surface® 2.0 SDK, you can easily create applications to take advantage of the next generation Surface computing device. The applications you create can be adapted for other Windows 7 touch-enabled devices as well.
You can find the bits at http://www.microsoft.com/download/en/details.aspx?displaylang=en&id=26716