When I was at TREXPO in AUG 2000, I asked Ernie that same question and this is how he told me to do it.
Get a round diamond sharpener like the one that DMT sells for doing serrated blades. Lay the knife flat on the edge on a table so that the edge of the blade is past the edge of the table. Start with the round diamond at the pivot and try to match the angle of the grind and then stroke it toward the tip. You should be able to tell that the diamond is making full contact with the ground edge by looking at it. Once you get it sharp, then strope the backside of the blade on a piece of cardboard to take off any burrs kicked up. If you are too heavy handed you may have to stroke the backside with the diamond once if you kicked up a heavy burr. I have done this several times to my Commander and it comes out very sharp.
Hope this helps,
Lynn