The only way I've done it is EWR-GRU on CO in BF, upgraded with miles, and then GRU-EZE on Varig (RG) in coach. I think they just tack the GRU-EZE fare onto your ticket. I was able to book all this thru CO telephone reservations.

Varig coach was not bad at all for the 2 1/2 hour flight. We got a hot meal (steak or pasta I think), free drinks, and IFE. I was able to get bulkhead seats no problem, and got the miles credited to my UA account.

You can do it with Copa but it will require an overnight somewhere (MIA or PTY probably) so it wasn't worth the trouble for me.

Edited to add: Correct me if I'm wrong, but DL doesn't fly to EZE anymore so that's not an option.

[This message has been edited by IAH_FLYER (edited Mar 20, 2004).]