I checked through the thread again, and cannot find the reference anymore. There was information about a hard plastic curved bulkhead, but I cannot find it anymore unfortunately.
Give the uniseals a try, let us know how they work out for you.
Read this link first, they might leak on thin material, and I am guessing your skimmer body is pretty thin.
http://www.aquaforums.com/forums/lof....php/t293.html