I've not seen PAST shooting vests, but they may employ the same recoil pad as their shoulder pads.
The type I use straps on over your shirt. Here's a link to Midway's site - - you can see what they look like.
http://www.midwayusa.com/eproductpage.exe/showproduct?saleitemid=680235
Here's another link that shows some other choices...
http://www.midwayusa.com/ebrowse.exe/browse?TabID=4&Categoryid=9210&categorystr ing=655***688***