TFTP Download for IE Lab Rack

RandyCCIE#TBD

guys - are any of you doing the internetworkexpert.com labs on a home lab rack using 2600 series routers? You need to TFTP boot IP Plus images that support OSPF v3, RIPng and IPv6 to do all the labs properly, however, I can only TFTP boot these images from ROMMON. I've set all of my environment variables in ROMMON so I can just issue the tftpdnld command and load the image, but does anyone know how to automatically load the image when i reboot the router? I've already tried the boot system tftp command from config mode and it doesn't work.
thanks all!
Randy