Help with Kooi Aap truck-mounted forklift controls

Hi All, This looks like a great place to find experts on oddball equipment like the forklift I picked up on craigslist. (I tend to take on pretty ambitious projects, and I always seem to be needing a forklift for something...) It's a Dutch truck-mounted forklift (Kooi Aap Z2-3). It's very capable with a 4500# lift capacity and about the same gross weight. It has side shift, a scissor extension, and a Kubota diesel motor. The problem is that the markings on the electronic controls are almost completely worn away, so I don't know what most of them do. In particular, I would love to know if it has some kind of slip-limiting drive for the 3 wheels. Right now, if one wheel slips, you're dead in the water (or dirt). Things I know: The upper left button is a "parking brake". No power goes to the wheels when it is engaged (the indicator light is red). One of the lower, smaller buttons activates the small hydraulic supports in front of the front wheels (for countering heavy loads). I don't remember which one at the moment... Does anybody have any experience with these forklifts or any thoughts on where to start looking for answers in the way of tracing out the hydraulic system, etc? Thanks! Ben