Sorry to digress... but if you have an in transit connection, I dont see why you would not be allowed to stay airside. Furthermore, since you are not going to enter Argentina, there is technically no need for you to clear immigration and customs... unless they now are doing a MercoSur entry in which case this may/would apply. Remember, MVD = Montevideo, Uruguay.

Every time I arrive from North America, there is an airline agent asking about connecting flights to Uruguay... such as the case mentioned here, and all the time folks with such connections are not sent to immigration.

Heramato, maybe you have some new information on this and would care to elaborate... but its my understanding that there is no need to leave the sterile area to make this connection.