Help taking apart nose gear strut

[Skymaster337B]

Herb, here's what I'm seeing in my parts manual. There are two "lock rings." Item number 12 and 20, for the top and bottom of the" ring pack support" #17. Additionally, at the bottom of the collar is a snap ring item #21, listed as "ring-retaining." I've removed item 21, but that was easy to see and access. So which internal ring am I missing because I don't see how to remove 12 or 20 until after removing the lower strut....in fact the book says to remove 12 and 20 after removing lower strut from the upper strut.

Thanks,

Rob