Start by connecting to your vehicle and entering the DME (highlight and let DIS perform a short test) then you will be able to proceed to the next screen and allow you to click function selection once there Follow the steps in the picture below.The VANOS test within DIS is accessed by following the pictures.
Once you have made your selections; simply click test plan and follow the steps given by DIS to get your VANOS tested!
Also, there might be slight differences in naming for cars fitted with MS45 DME's but it should be easy to know what to look for now. The M3's have a completely different function selection screen.
The test checks wether the valve can reach full retard and full advance positions, if it can hold a position (leak down test) and also test how fast it reacts to changes and if it's within specs.