Eventually was able to get it by using the following:

if keystate(17)=1 then phy add rigid body torque id,cos(camera angle y()),0,-sin(camera angle y()),4
if keystate(31)=1 then phy add rigid body torque id,cos(camera angle y()+180.0),0,-sin(camera angle y()+180.0),4
if keystate(30)=1 then phy add rigid body torque id,cos(camera angle y()-90.0),0,-sin(camera angle y()-90.0),4
if keystate(32)=1 then phy add rigid body torque id,cos(camera angle y()+90.0),0,-sin(camera angle y()+90.0),4

Hope it may help someone else as well.

Edit: Attached a Demo of my progress.