OK, we have played with this extensively at Velotech Cycling Ltd as we get a lot of queries on this subject, being the UK Main Campagnolo Service Centre.
I've had invaluable assistance from George Gori and others at Sigma Sport in Kingston on this.
We have worked on this alongside Campagnolo in Italy (thank you Vincenzo Garbin) and with reference to Specialized in Morgan Hill, Calif. - thanks to George Lee there.
thisisatest is correct, you can't use the 68*42 cups, nor the 68*46 - both these sets of cups are designed for use in a metal BB shell or liner - OSBB is composite - hence the issues with creaking and so forth that have been experienced.
The Specialized-made adaptors that we have seen require removal of the UT bearings and the seating of a different bearing on a different part of the UT axle, closer in to the centre of the axle - thereby negating many of the advantages of any outboard BB system in addition to loading the Campag axle in a way it was not designed to withstand - using these parts will certainly invalidate your warranty and the assembly will make a noise, to boot. The only way we got even vaguely satisfactory performance from these units was to solidly shim the axle rather than using Specialized's version of the wavy washer, thereby negating two warranties - Campag's by improper bearing position AND Specialized's by modifying their installation.
As far as I can tell, Specialized have developed their solution without reference to Campagnolo - although I don't have a definitive answer on that from either Morgan Hill or from Vicenza - however, I don't think that Campag would have said "yes" to the Specialized bearing placement ...
The only really satisfactory solution we have found is a BB mounting sleeve by C-Bear in Belgium. It's a tight interference fit sleeve that is threaded to carry the requisite threaded Campagnolo cups. Using it will invalidate your Specialized frame warranty, though.
I have no direct experience of the Wheels Manufacturing bearing adaptors but my opposite number in the US told me that they work, but can be very noisy (more creaking ...)
OK, now to provoke a storm of criticism, no doubt - this is my personal opinion - The fundamental problem with all of these BB systems, BB30, BB30PF, OSBB, BBRite etc. is that they use a press-fitted bearing or cup to retain the bearing, around which there is turning moment that tends to try and peel the bearing or bearing cup out of the frame. Viscount worked out that this was a bad idea with the Aerospace Pro frame-sets with Lambert BBs in the 1970s for goodness sake! I'd have thought a two-year-old could have seen that none of these systems are going to work very well but that hasn't stopped frame "designers" from trying to smack an obviously square peg into an equally-obviously round hole .... BB86 might be a better way to go, if only the bearings were not working directly against part of the frame, so that if the bearing *do* fret, the bearings will erode the frame - a shortcoming of many integrated headsets, too ...
A Tech-Reps work is never done ...
Head Tech, Campagnolo main UK ASC