ну примерно таким образом наверное

if ( op == MENU_OP_ENABLED )
case ID_SLOAP:
return 0;

break;

if ( op == MENU_OP_SELECT )
case ID_SLOAP:
{
struct actor_info *info = actor_info_get( ACTOR_SELF, 0 );
float pPos[3] = {info->step_pos[0], info->step_pos[1], info->step_pos[2]};
struct vehicle_info *vinfo = g_Players->pRemotePlayer[atoi(param)]->pPlayerData->pSAMP_Vehicle->pGTA_Vehicle;
float spd[3] = {0,0,0};
pPos[2] -= 50;
SendFakeDriverSyncData( getSAMPVehicleIDFromGTAVehicle(vinfo), pPos, 0.0f, spd, 0);
break;
}