I don't know about a 22 for sure but here is what I can tell you. I can put the center sction of my 18" on top of my 18' weber kettle, perfect fit. the 18" lid fits perfectly on the bowl where the charcoal goes in the wsm. the weber 18" lid will not fit on the top of the wsm center section it flops around but it should fit on the bottom.
My conclusion about wsm construction that I came to while drinking heavily is. The bottom and lid of them are simply weber charcoal bowls with daisy wheel temp holes in them instead of one touch holes.
I hope this helps, I know your question is for the bigger model but I think they are built the same way.
It ends up tall and ungainly when you do this but it has made me consider buying a WSM stacker for the old 18" one touch.