Isn't it possible that it has an retractable internal probe that stores flush with the skin, and then pops out for pit stops? The frog version of the Jaguar seems to have one that is barely visible. Maybe we ain't the only guys the Russkis steal from.
The preproduction aircraft doesn't have a probe, and while one could be added, it would only increase the weight and complexity a bit more.
Also, the Russians don't seem to have placed nearly our emphasis on aerial refueling: I can find reference to only one Air Regiment of Il-78 Midas tankers currently in operation.