I don't remember in complete detail, since it's a modification you do to the "caddy base" itself - specifically to the "barrel" that you turn with the key.
You have to remove the whole thing from the HDR to do the mod.
I think I just removed it and disassembled it to the point where I could see what the turning of the key would do.
I could see that there was a "pin" or "pole" sticking out of the "barrel" that the key turns. (goodness I hope all this makes sense). I simply unscrewed/removed that pin/pole, since that is what locks the caddy in place.
Now I can leave the Barrel in the locked position (since that connects power to the caddy), but still remove/insert the caddy.
Sorry I don't have pictures of it - I'm too lazy to disasemble my HDR now, to take photos of it