Check to see if it can send ASCII characters (i.e. letters, space, arrow keys, etc.). If it can, you can assign one of the buttons to send the ASCII character for the key command that is assigned to the Undo. It is possible with the Axiom Pro but I am not sure about the Oxygen. Concerning the Hypercontrol and Directlink utilities, there are personalities available for Cubase 6 (ver. 1.1.6) that are working nicely here. I have seen some posts by people using that personality with C7 with success.
HTH
J.L.