synchronization between cubase 5 and midi-controller

Hello to everyone! This is my first post here.

I have installed cubase 5 in my PC (using Windows 7) and i have connected the midi controller i use
which is the Studiologic VMK 176 plus into it.
Also, i have loaded in cubase all the VST instruments i have and by adding midi tracks i can easily record
or just play using every kind of instrument i want to use.
As far as my main purpose is to play in live performance, i am trying to find a way to move through tracks
(as each track means a different sound for me) by using the buttons of my midi-controller. In other words
i am facing problems with the synchronization between the cubase 5 and the midi-controller.
I thought that it would be an easy thing to do, as in the Midi Port Setup my controller is visible and active
(with the name Studiologic-MD).
Furthermore, i would like to use the switch buttons of my midi controller during recording in cubase.

I believe I was comprehensible.
Anyone who can help me??

Thanks, Paris