Open AppleYukon2.kext/Contents/MacOS/AppleYukon2 with HexEdit 2.0 (freeware).
Click to view attachment
At the picture you can see what and where
1AF20: C6 45 E2 00 C6 45 E3 11 C6 45 E4 22 C6 45 E5 33 C6 45 E6 44 C6 45 E7 55
Change these digits to your Mac-address, save and reboot. Now I see my MAC-Address

In other version the address may differ. Find by context (hexadecimal)

EDITED:
For 64bit (x86_64 arch) you have to find
C6 45 C0 00 C6 45 C1 11 C6 45 C2 22 C6 45 C3 33 C6 45 C4 44 C6 45 C5 55