Problem solved. Tons of spended time reading chineese sites did it.
If anybody needs it: The watch model is AD-838, manufactured by:
www.andalong.com
Video Converter must be NXVConverter 4.10, older versions not work, Picture Converter is NXPhoto 1.0.2, olders not work too. These programs can be found somewhere in the net, they work perfectly.
Thank you all. The thread may be closed.