Hi Markus,
what I am doing is WMM mapping.
Client skype application is using DSCP value 46. According WMM standart this value belongs to WMM category "VI" (video).
So it means I am getting over wireless from skype WMM category "VI" and on AP I am mapping this category to DCSP value 46.
wlan ssid-profile "XYZ"
wmm-vi-dscp 46
wmm
wmm-override-dscp-mapping
It means that outer GRE header will have now DSCP value 46.
According to my test, controller will then decapsulate GRE packet and will use on his uplink classicall ethernet packet with client DSCP there. So it means on uplink of controller I have again DSCP 46.