Kinect SDK 1.7 - How to work with both hands

Kinect SDK 1.7 - How to work with both hands

I´m trying to work with Kinect SDK 1.7 in WPF and C#. I found some
tutorials, but nowhere I cannot find how to work with both hands at once
(in my Kinect Region i only see just one hand at any time).
Please can you help me, how to do that? I´d like to this this for zooming
in maps!
Thank you very much!