3ds Max :: Customizing A New Button Icon

I had this new script which is used in Unwrella2 so I placed it in the user interface as a new button in the tool bar, the problem is it has no icon so, I wanted to customize one for it. I start searching tile I found how to and I followed the description..I customize a button icon 24*24 it had to be *.bmp 24-bit(I also found that to have an alpha channel it has to be 32_bit 8red 8green 8blue 8alpha) or 16 bit it must contain an alpha channel which I did all of this I even toke one of the original ones from the UI folder and I customize it then every time I copy the new button in icon folder and restart max 2012 and go to “edit button appearance” and search for the new button nothing there I named the new button right “group-name”_24i.bmp but still the max 2012 don’t want to read it.

in the image attached a button icon which should give me a new group called Unwrella with two buttons. I even found some original buttons which is split in two file (file *_24a.bmp contain the Alpha as RGB) and (file *_24i.bmp contain 24_bit colored RGB) I even tried this but still max 2012 don’t read it.