howto activate special keys on keyboard?

[mclien]

I have a mini keyboard/touchpad combination.
this one. It is quite nice as a remote substitute.
Of course the is no config for this via dpkg-reconfigure keyboard-configuration
So my question is, how do I approach this best. I guess I get the keycodes with the programm "xev". But how do proceed from there?
Is there a way to generate a new config for that, which then will be select-able in the dpkg-reconfigure keyboard-configuration or is the old xmodmap still around to make it work on user basis?