I know SkyTeam is pretty weak in South America, but I would like to fly on DL there then utilize one of the Air passes for intra-South American travel. I've looked at OneWorld's Air Pass as well as LAN's, but they of course have restrictions that preclude me, flying on DL, from taking advantage of their Air Passes.

Alternatively, I've found the Mercosur Air Pass, which seems great, but I have run into the following problems:

1. I have a $500 credit on DL, so I'd like to purchase my tix via delta.com
2. I haven't found a travel agency that will let me just purchase the Mercosur legs without purchasing the RT from the US
3. Has anyone suceeded in doing this before?

Thanks!