Again, I agree with Clubman. I don't know of anyone who has tried the modern 5-sp shifters on an old 4-sp. At issue is how much cable each one pulls; and I just don't know.
Hmm, given that I have a new 5-speed bar-end shifter on my Super Course MkII and a couple of wheels with 4-speed hubs around (FM or FW), I might need to try and report back.
Neal