No. FX is not a security, it's a cash swap of currencies. In the US you can get around 50-1 at some banks. Over seas in the UK I've heard of traders get up to 200 to 1. Crazy. Futures on FX and options on the futures are futures products. I don't do much FX right now. We concentrate on equites/options and futures and options on futures.
By the way, a statement on the OneChicago site confirms that SSF's are not eligible for portfolio margining. "Portfolio-based margining (e.g. SPAN margining) is not yet permitted for customer positions in security futures. Firms will nonetheless continue to receive SPAN files that reflect the appropriate minimum margin requirements." http://www.onechicago.com/?page_id=119