Evildog, I think he is referring to the pins on the front of the frame that engage the barrel, rather than the pins found on the rear of some cylinders used as a "safety" notch.
I have had the pins come out on a 1851 steel framed Pietta.
I simply used the red colored Loctite to secure it back in the frame, and have never had an issue since.
Just order a new pin, which can be had here through VTI gun parts.
Here is a link to the 1860 Army page of the Uberti at VTI:
http://www.vtigunparts.com/store/sho...erti+1860+Army
Part #23, and they are $1.75 US plus shipping.
I sincerely doubt that you would have a problem ordering this part internationally, since they are only pins- which could be for anything. If you do have trouble, a good gunsmith should have had this taken care of with nothing more than some steel rod, hardened if possible, and cut to the correct length and installed.
Once you get them, gently hammer it into place after coating it with Loctite. Just be certain to wipe any excess off the outside of the pin.
If they cannot ship them to you, there should be a Uberti parts distributor around France or Italy that should.
I take it that it would be a "faux pax" to obtain a Kirst or R&D cartridge conversion cylinder in .45 Schofield or .44 Colt in France for that revolver without paperwork? I just ordered one myself after shooting one my friend had this past weekend.