It is no more [or less] difficult than importing a gun from anywhere else outside the country. Call or visit your local BTAF office. I think you will find them helpful & they can tell you exactly what you need to do & have in place to get it done correctly.
I looked into it a number of years ago in Beunos Aires, but the problem was [this was w/a dealer, not an individual] the dealer did not wish to be an 'exporter' due to a lot of extra regulations on his end at the time. I could have bought the gun [an English BL 28 SxS] right then and there, perfectly legal at the time and no hassle, but had no legitimate way to get it back here w/o having the paperwork in place beforehand. Aside from forms required here, you will have to have the gun go through customs here and also find that the importer's name will need to be affixed to the gun. Some importers are better skilled at doing that in a unobtrusive manner than others, so its best to know beforehand how that is going to be addressed.
There are well qualified importers here on this board and it might prove beneficial to ask one of them to do that work for you, should they be willing and then to send the gun along to an FFL near you for final delivery. Just some thoughts.
adendum: I'm not familair w/Uruguay's firearms export laws, but their Consulate's office here can likely provide you w/that information.
Last edited by tw; 09/03/13 11:15 PM. Reason: Was going to add 'present' to the ref to Uruguay's export laws, but decided against it.