[HECnet] Writing vms boot CDROM

Can someone help me out with instructions on burning a VMS boot CDROM. When I bought my first alpha, it came with an additional internal drive with the OpenVMS 7.2 install cd copied to it. I now have a writable CDROM drive on my Alphaserver 800 and would like to make a install CDROM of vms 7.2 as a backup in case that old drive fails. Sadly I've never written a CDROM under VMS (only used tape commands back in college days). Anyone know the relevant commands to setup the CDROM and burn it in the right format for booting vms? Sent from my iPhone