Report Dell BIOS serial number via WMI?

How can I have a programmatic query (from a program required by my company) report the Dell BIOS hardware serial number? I think this program is querying via WMI.

I've poked around in config.pvs, and nothing jumps out. I've looked in the thread http://forum.parallels.com/showthread.php?t=32400, which provides no answer to this question. Forum searching has so far not produced an answer for me.