I'm looking for a way to put in a serial number , of my choosing into the CMOS.

My client has software,that can keep an inventory of all his machines from the server, and does this by having a serial number from each client that it gets from the BIOS. It also give him all the hardware info about the machine as well.

Does anyone know how this can be done?

It would be on an Award Bios
(current versions).