OK, I got mine and did it. It's a bit of a pain, but not exactly hard. A drill press is recommended.
Mine is a planet so take that into consideration, it may be different.
The biggest problem is you have to drill a recess hole that the shell holding the screw fits into.
That's the OUTSIDE of the leg as it came from Berlebach, and the hole goes directly under the knob. You have to put another one of these in the same leg piece on the same side (assuming you want the knobs on the same side). If it wasn't for this it would be much easier. To do this, I found it easiest to take the legs completely apart: remove the top plate bolts, remove the one screw holding the metal plates that are at the top of each side of each leg (6 total), remove the tray from the legs (2 screws each side of each leg, and then come off with a little twisting and pulling, you do NOT need to remove the bolts holding them together, and at the TOP of each leg two stops that are little brass bullets that keep the leg from sliding out. You do not need to unscrew the bracket that is already there and I found it simpler not to. You do not need to remove the feet, though if you have the spikes installed be careful of your feet!
Then slide the center out of each leg out, and the side you need to drill can be removed by just sliding it out as well. Leave the original bracket attached to the other side.
Drill the recess in each side, slide the new bracket in place (be sure to get the little mysterious outward pointing cutout on the inside) and put it back together EXCEPT the tray. Make sure it all fits and the labels are on the right side and so forth. Tighten lightly both sets of leg brackets.
Now drill the pilot holes for the new brackets (being tight they stay in place), and add those two new screws.
Then what I did was assemble the top plate lying down for the first two, and standing up to add the third.
Then with it in tripod shape on something where the legs won't slide out (carpet works great) one by one attach the accessory holder back in place. Be aware the legs can completely go outward until this is attached. It's a bit of a pain to get the holes to line up but you can.
NOTE: It is really important to figure out exactly where you want the bracket, and make sure it will not get in the way of something like the accessory tray. The leg will extend only down to this bracket. I have mine mid-way up the leg, so my tripod will only extend halfway -- that's more than enough since I use it totally collapsed, and I think (THINK) that the bracket being higher in the leg will make it more rigid. Mark it (like painter tape) before taking it apart, and collapse and extend the tripod and make sure it won't hit anything.
Here's the final result.
The comment that you can't retrofit is clearly wrong, but it is not completely wrong. This is not something that someone who is a klutz working with wood and tools should attempt. You don't have to be a craftsman either, but some experience is nice. A drill press is not really required but sure is handy to get the right depth and location of the recessed hole. The good news is that it's not one where fit is critical, it just needs to be big enough and not show (for cosmetic reasons), there's no support provided by the edges of it, you just need to get the wood out of the way. I did not find the wood difficult to drill at all, it's good fine grain and while not soft, it is easy to work with. You should drill pilot holes for the new screws though. Also, be aware there are two different screw sizes -- the brass bullets have a different size, keep the separate.
I recommend taking a piece of junk wood and drill first and test to make sure it is deep/wide enough, but no deeper.
Probably 2 hours total, most of the time being really careful not to scratch things up.
Edited by Linwood, Yesterday, 04:58 PM.