It seems like CS:GO is not able to recognize the buttons of your mouse. What you can do is to create some macros in your mouse driver.
Keep in mind that I am using the driver tool for the Kone[+] and your driver window may look different from mine. If someone has the same problem but is using a different mouse you can go ahead and try reproducing the same for your driver.
For the first step you have to create a new macro set where you can collect all your CS:GO macros. Just open your driver and execute this 4 steps below.
Click on the Image to enlarge it
After that, select your created macro set and press the new button at the left bottom. To assign something to that macro you press the start record button and press the button which you would use without the mouse. For example the number 3 for the knife.
If you have all function assigned, press the ok button to save your changes. (Keep in mind that you can create more complex things in the macro manager. You also can use the advanced editor.)
The last step is to assign the created macros to a button on your mouse. But before you go ahead and assign a button you should keep in mind that you lose that function on that button.
So you should add all your CS:GO function to a new mouse profile and switch to that profile if you playing CS:GO.
Pro tip: You can assign a profile to the game so everytime you start CS:GO the profile is selected automatically. If you press the WP button this profile is selected automatically if you change to windows.
To assign the function to a button you just select the number of the button you want the function to be and select your macro on there.