Darn! So this can't be done!
I was also wondering how to do this, but I guess its out of the question now. Oh well. Another, similar question I have is whether you can detect the current animation of the player (e.g. is he laying down, standing up with a rifle, standing up with a pistol, et. al). I doubt it is possible, but if it were, perhaps you could detect whether the player is standing in the regular, unarmed civillian pose, or whether he is in the soldier-with-a-rifle-pose...?
Igor:
I've gotten that command to work before. You just say something like:
bob selectweapon "rpglauncher"
It seems simple to me. What exactly are you having problems with?