Ok, I did this and it works:
//RCS PITCHUP
th_rcs[0] = CreateThruster (_V( 0, 2, 3), _V(0, 1,0), MAX_RCS_THRUST, ph_rcs, ISP);
th_rcs[1] = CreateThruster (_V( 0,-2,-3), _V(0,-1,0), MAX_RCS_THRUST, ph_rcs, ISP);
th_group[0] = th_rcs[0],th_rcsd[0];
th_group[1] =...