Trading in a foreign currency with a US broker

I live in the US and have money in Canada. I don't want to convert the Canadian dollars to US right now because of the exchange rate.

Are there any US brokers that allow for a Canadian dollar account?

 

www.interactivebrokers.com

 

Thanks. I emailed them a day ago and haven't heard back yet. I called and hung up after 12 minutes on hold.

 

Seemed like the same old IB story

 

How does a foreign currency account work? When I put on a trade do they convert the amount needed to US dollars and then convert back when I close the trade? That would mean I end up speculating on the exchange rate for the period of the trade.