How To Get MAC Address (PC is Shut-down) From Logs, Command Prompt ..anything

Dear Experts,

I would need to wake a PC remotely using its Mac Address.

Problems:
1) I don't know the mac address
2) The PC is currently switched off
3) The PC, when on, has a Fixed IP address, so in the DHCP cache
    of the domain controller doesn't appear

What I have:
1) Access to a Windows 2003 domain controller
2) running MS-SQL, Exchange, DHCP, DNS, Active Directory and so on
3) I'm the administrator

normally and arp -a would do... but the PC is currently switched off...so i guess the only way to find
out is to query some logs...or look some properties in Active directory... but Couldn't find anything so far.

As said, the DHCP service would help as it gives the last assigned IP and MAC address...but the PC ha a fixed IP assigned...so no record in there..

Thx!