Navarros -
The statement you read is wrong. You can do all sort of editing on the hard disc and still do a high-speed dub. The only limits are a) that you do the dub in the same speed as the original recording and b) that the program(s) you want to HS dub to a DVD-R are less than the total available bits, which you can see in the dubbing window.
Walk us through - - - precisely - - step-by-step - - exactly what you're doing, and we should be able to figure out where you're getting off the track.
PS: it might be the media. The E80 & E100 do a little test of each disc to see if it can, in fact, do a high-speed burn, and sometimes it will drop down to real-time speed if the disc fails the test. (More commonly, it just goes through an error process and won't use the disc at all) Try another brand just to be sure.