COULD be a client-sided hack since the Archlord programmers only taken act on encrypting every file, but you can easily decrypt and change whatever you like. I managed to get into the ConquerOnline Database (Which is way more advanced game than this) so Archlord(c) shouldn't be that much of a problem to do. If job's are clientsided, that means if the server reads the job names from a INIfile, you are able to change name into another class yet using the original job number, therefore equip other job's equipment.
Everything is possible if you have the right amount of knowledge ;)
Regards Emme