Legality Of Marriage In A Third Country

My wife (Thai) and I (American) were travelling in South America when we decided that we would get married while on our trip. Knowing that we would eventually want to settle in the U.S., we went to the Thai Embassy in Buenos Aires, Argentina. We discussed the situation with the embassy staff, and they assured us that getting married in the Thai Embassy is the same as if we got married in Thailand. So we went through the entire process, and even had cake and champagne for the Embassy staff.

Fast forward to today when I presented our I-130 petition to the USCIS Office in Bangkok to begin the immigrant visa process for my wife. I was told that since we were in Argentina when married, the marriage had to have taken place under Argentine law. I explained that although physically in Argentina, we were legally in Thailand when we were married since the Thai Embassy is considered Thai soil.. I also told the lady that it was not my contention that the marriage was legal in Argentina since that was not our intent in the first place.

I told her that the U. S. Embassy in Buenos Aires had told me that they would not recognize a marriage even done in Argentina since neither of us were Argentine. I also told her that under Argentine law, we could not get married there since neither of us were Argentine and we did not have residency status. The USCIS lady kept going back to the State Department regulation regarding the "Host Country". She even threw the asinine suggestion that we get divorced and remarried in Thailand. I couldn't believe my ears at this.

So my question is how do I prove this "Lady" wrong. I am not really looking for people who might hapen to agree with me. Rather I need a specific statute to prove to this lady that she is all wet.

Can Anyone Help???