It actually does, on the bottom. It is just hard to see. (Edit: Perhaps it actually doesn't, now that I take a closer look in ModView... I may have screwed something up there. Nice catch!) I just typed out a response to this part of your post, but it disappeared while I took another look at the skin... O.o
Anyway, I said that I tried many times to get it to look right without using any source pictures, but couldn't, so I just googled 'kneepads' and based them on what I found there, which explains the rollerblade pad style it seems to have. I considered leaving the kneepads solid (without those holes) but it seemed far too plain like that... If I get any ideas on how to make it look better, I'm gonna change it as soon as I can. Perhaps if I didn't work on this skin when I am half asleep, it would turn out better. XD I'm horrible with shaders. If I can get em to look decent, then I may just go for that, but I dunno if I can.