Well, JB, thats were your wrong, the armoury_entity only contains SMGS, rifles, shotguns, equipment. No handguns... I decompiled the aim_map_usp to have a look, it uses a totally non-making-sence system of game_equips and things like that. The equips target the weapon:
Ammo_45cal or something like that, which still doesnt make very much sence!
Stupid counterstrike...