i am sure that you can use any lever. i believe that armstrong had them on
his time trial bike with non ax brake levers - i can't remember exactly what kind.
i used to have them on my raleigh road ace back in the mid 80s and there
was nothing special about the way they work, so i'm sure that any conventional
lever would work. i'm too retro to know anything about modern levers working
with the ax calipers tho'!
for some ax appreciation check out this page! >>http://www.redlanterncycles.com/rides2.php?id=51#1
1989 TvT Carbon Fibre, Oakley Factory Pilots & painkillers . ..
..what else could you possibly need?!!