is there any way to change dynamicaly the MAC on a Cisco 350 PCMCIA?

ifconfig tell me :
eth1 Link encap:Ethernet HWaddr 00:07:EB:30:F1:AE

When I put the card in monitor mode doing:
echo "Mode: rfmon" >> /proc/driver/aironet/eth1/Config
ifconfig tell me
eth1 Link encap:UNSPEC HWaddr 00-07-EB-30-F1-AE-00-00-00-00-00-00-00-00-00-00

How curious...