Two ways to do it depending on how much fab equipment you have. You can do all the forming which is shown in the link or you can use flat stock and weld all the seams. Oh yeah the third way, a hybrid of bending and welding.
The second way is by far easier with less figuring and equipment needed. I will give you a quick run down. Take your face plate with the top piece of flat stock (44 5/8" long) welded on at a 45 degree angle. Hang that on your 763 and clamp it tight to the quick tach on the machine. Make sure everything is square. Cut out your bottom plates with holes in them for the pins to protrude through. Hold them up to your skidsteer's quick tach, line them up an run your pins down. Make sure that the tapered side of the pin hits the back of the hole, tightening the unit up as it comes down. This could take some tweaking but is necessary to get out all the play. If you cut your holes to big, just fill with a little weld and grind. If it looks good, tack it and weld. I call this the "poor man's tach plate".
Hope this helps and good luck to ya!