Is it possible to have Peace Walker like button mapping in MGS1, 2, 3? Or how to have efficient gameplay?

I ve bought MGS HD Collection, since MGS1 wasn t part of the pack, I started with Peace Walker (thinking it was a spin off, shame on me, it s between 4 and 5).

Now, I m starting MGS3: Snake Eater, and I really struggle with the command, which are the same for MGS1 and MGS2.

In MGS:PW, L1 is aim, R1 is fire, hold square or press R2to change weapon, hold triangle or L2 for changing items.

In other MGS, it feel like all other the place, R1 is for first peron (and so aiming), square is fire when you unhold the button after pressing it.

Why do I have to use square, and so move my thumb from the analog stick, if I want to fire? Furthermore, it prevent me from walking and so avoid enemy fire, or adjust my position if the target move out of my filed of vision.

I m still on the first mission of MGS3 after 2hours of playing, I feel like a MGS:PW button mapping would have taken me to the second mission easily for the same amount of time.

All I saw in option (for MGS3) is Classic or 3rd person View (which is exclusive to MGS3HD), and no "Button mapping" option whatsoever.

How am I supposed to play to take advantage of using square to fire and R1 for 1rst person view?

EDIT: Expanded the question to MGS1, 2 and 3.