I would like to use some of my bitcoin to short a currency I think will fall, relative to bitcoin.

I think a nation's currency is going to explode.  I am bearish on this nation's money.  I am bullish on bitcoin.

I have an account at havelockinvesments.com, they offer to sell me a share in a mining pool, that's cool, I can see my profits as it goes up.  But I want to see profits in BTC terms as the currency I am speaking of, goes down.  "Down" meaning people are ditching this currency, and buying bitcoin.

Where should I set up an account to do this?  Thanks in advance!