Just reading ur comments and noticed your set up very similar to mine. Just about to use the 10-22 in the ikelite housing with 8" dome port, but the gear sleave and focus ring don't fit. I see you have a similar wide angle and wondering what I am missing? Is there a specific extension or additional gear sleave? Only came with a standard size one?
Split the answer off so not to hijack thread on bouyancy.
For the zoom clamp, check out :-
For the Port, Ikelite have a range of extensions (all the same diameter) in different lengths. These screw into the back of the port to account for the length and focus point of the lens.
If you, or anybody else wants any more info just shout.