Funny I have been reading both sides from the BBC for the last year.
The trick is Salmond isn't saying much. he has no plan B if various parts of his plans fail. He just isn't saying things like we would still use the sterling if the UK didn't want a currency union. He can't imagine a scenario where a currency union wouldn't be agreed to. or a scenario where Scotland wouldn't immediately become a part of NATO or the European Union. He thinks that every thing will stay exactly the same yet Scotland would be independent. That just isn't possible or realistic. Some one is going to tell him we aren't bending rules just for you after the Yes vote and Scotland will get screwed.
Salmond Thinks he can bypass all the EU rules regarding joining the union without having the currency just because Scotland was a part of the UK. All the EU has to do is tell him no on just that one point. And his whole plan will fall apart.