How do you take a weapon from a dead enemy in Metal Gear Solid Portable Ops

all you do is hold square while on top of or in front of the enemy while theyre on the ground, this will pick the person up. Then let go of square to drop the person and an item will drop near them; if theyre alive you can do this twice but if they are dead, you will only be able to retrieve on item from the body.
However, if you have regular MPO (Metal Gear Solid Portable Ops) instead of MPO+ (Metal Gear Solid Portable Ops+) you will only be able to pick up items instead of weapons from them even if you see them holding a weapon.