Also, if Bitfinex starts supporting margin for a new currency in the future, and you don't want to wait for me to add support to it, all you'd need to do is add it to the CurPairs table.  Just need to add the currency code to curSym, the name of the coin to the curName row, and set status to 1 (leave the id blank and it will auto increment).  After that is should be an option in the dropdown menu.  Its also possible to hide currency that you don't care about, just set the status to 0 on any you want to hide.