Ouch.. I had to see this only a couple days after I installed those plates.. Now they're sort of tedious to get back off!
Hopefully you've already got this figured out but if not, i can at least tell you that they aren't overly complicated. They engage the 3 17mm bolts behind the axle shaft and also bolt through the hole for the 7/8" pin that usually mounts the 3pt arms. There is a flat bar section welded on horizontally which serves to center the c-channel 'frame rails' of the backhoe under the tractor. If i was missing them, im not entirely sure i'd replicate the factory design. Might be tempted to change them up somewhat..
Also, if you haven't already got the thing mounted, do yourself a favor and don't unscrew the stock bolts, install these thick plates under them, and reinstall the stock bolts with half the thread engagement and strip them out. I had to order a set a 12x1.75 heli coil thread inserts because the previous owner of the tractor im fixing up for a buddy had done just that.
