If you have linux installed already, you could use linux tools to get the md5sum of the cd you want to copy, copy the cd and then check the copied cd to make sure you have the same md5sum as the original. Check my post on linuxiso.org forum re using th rawread script to get accurate md5sums of cds:
http://www.linuxiso.org/forums/viewtopic.php?t=7456
Also, check out the link I cite there re some excellent info re creating accurate copies of linux install cds for redistribution.
Finally, the quote you referenced doesn't make a lot of sense to me. If your original cd has the md5sum info on it, the copied cd from the image should also have it one would think. I have some rh 9 cds that I burned from isos and will try a direct copy of one to see if I get any md5sum errors from the rh install routine.