IPhone : UIBarButtonItem TwoTone

I was wondering if there is a way of doing a twotone image using fontfiles on UIBarButtonItem

so that the color of the middle can be one color, the outer color can be another color, but the background can still be transparent

I know that if i use fontfiles i can use tintColor to set the text item can be 1 color

and then use background color to another so that middle will be another color, the problem with this is that the background (so if the item is round, the remainder) would now be that color, which looks ugly

thats what i want to be able todo so that it doesnt affect the background color