Altitude calculation with GPS module is wrong

[Guest Elch33]

I am using Omnia Pro's GPS module quite frequently. Especially with Navigon MN 7.4 and GPS Tuner Atlas it works superb. The only thing that annoys me is that the altitude calculation of the GPS module seems to be wrong. It always shows me an altitude which is roughly 40 meters higher than the official altitude on topographic maps. I also cross-checked this with my other pocket pc (HTC Advantage) and there the altitude is displayed correctly using the same programms. In GPS Tuner I can correct this mismeasurement manually. However, in MN 7.4 I can't do that.

Does anybody know any registry hack or so, to make an altitude correction for the overall device ?