oh, if you have ssh, do you have full access to the router? i have looked a bit at the firmware and it appears the mac addresses are set by /etc/runoam.sh during boot. it gets the addresses from nv memory (some mtd partition). it reads mac address by cmd "flash get ELAN_MAC_ADDR". the best thing to temporarily set mac may be to copy commands from runoam.sh except the last line (which executes the cmd) and type "echo $exeCmd" which will display the command which would be executed to set the mac addr. in that change to your desired mac.