Some players may find themselves playing the game without a scroll-wheel mouse or a scroll-enabled touchpad. You can still zoom-in and zoom-out by manually assigning new hot keys.
First, you must be using user-defined hot keys. Edit your hot key (.xml) file and add the following line:
Restart the client. You can zoom-in/out using PageUp/PageDown button in-game. You may assign a different hot key by changing the parameters (PRIOR=PageUp, NEXT=PageDown) above. Ensure you do not have more than one function assigned to the same hot key.
For smaller units of zoom, reduce the number within CamWheel command to -1 and 1.