Need to have NumLock on in Z640 BIOS. Know how?

In all our earlier HP workstations there was the BIOS option to have the NumLock turned on during boot.  The default is to have it off, but it is an easy fix.  We use the NumPad for a bunch of important shorcut keys.  I cannot find how to do that with our Z640s, however.  Any ideas?

Thanks,  Scott