start Nero, go to "file - Options", there you choose "expert options" (or similar), there is the section 'overburn', where you input 99:00:00 next to where it says "absolute maximal overburning size" (or similar). Be sure to tick the field at the top where it says "activate Disc At Once CD overburning" and the bullet next to "absolute" has to be ticked as well. I am not sure if this works audio-wise with normal 700MB / 80minutes CDRs. At least, it seems to work with up to 830MB on a 700MB CDR.
BUT: possible that some CD burners don't support overburning, so in some cases, it helps to put the newest firmware on the CD burner