I used to have a VMS4 so can offer a couple of things that it took me ages to find - actually found them on here - I'm also assuming you are using the standard mapping of the VMS4 as it comes from either the CD or downloaded.
On the top of the VMS4 there is a rotary control marked effect (it has a white marker not a colour/clear marker). If you press the shift button and turn this rotary control it will scroll up and down the browser and when you press/push this rotary control it selects the line highlighted item in the scroll window (you need to keep the shift button pressed as well). The effects knob on the left side of the controller scrolls the file folders, pressing it will open and close folders, and the one on the right scrolls the files themselves and pressing will load to a paused deck. (You can press either shift button, left or right, either will work fine i.e. you can press the right shift to use the left rotary etc)
I fould these were more than adaquate for searching and loading tracks although I didn't find a way of loading tracks from the side list of automix list. If you want to use the main jog wheels to do this I don't see any reason why you can go into the configuration set up and then use the mapping options to copy and paste the effects mapping to the jog wheels so you just press shift and the jog wheels will do the same thing - sorry I can't try it to check this as I sold my VMS4.
Please remember that the VDJ LE version of the software that comes with the VMS4 will not let you change these mappings as it is a limited edition version although it will give you full funtion for 21 days. If you have purchased full pro version of VDJ then it will allow these changes ongoing.
Hope this helps though.