Okay Pony, pony, pony LOL, I took your image and did some outline work. This is what I cam up with.....
In this image, you will see that I did a basic outline of what appears to be the shin part and the shoe part. The shin is yellow and the red is the shoe. I think the white area is fabric and is not part of the armor by the shin.
Now in this pic, I took the shin and the lighter yellow is the area that I feel would be covered by that back part that appears to be connected to the shoe. This
(lighter yellow part) would obviously be covered and not seen.
Then in this pic, the lighter red/pink would be the area that is covered and not seen from the top piece that appears to be covered by the shin so I guess it wouldn't really matter what this part looked like. As long as it is modeled so that it can fit over top of someone's shoe. With as high as it seems to go, I don't think that should be a problem.
NOW seen here, I BELIEVE that this part can be seperate, BUT it SHOULD be modeled so that it fits over the shoe and NOT have it connected to the shin. This way, this piece will fit properly over the shoe and be sized correctly, but model it seperate from the shoe (i.e: don't fully connect the pieces; keep them in 2 seperate parts).
So in the end, I guess you would end up with models like this:
With of course the 2nd and 3rd image being together in ONE model, but 2 seperate pieces. Do ya get what I am saying? XD