3DS Max 2016 can't change button appearance


Hello, Im tring to make a simple toolbar (3ds max 2016) with the “Customize User Interface” menu and all works ok until I try to chang the appearence of the button. It just show me the button desings that come by defoult. I´ve put my custom buttons on several folders like “C:\Program Files\Autodesk\3ds Max 2016\UI_ln\Icons”, “C:\Program Files\Autodesk\3ds Max 2016\UI_ln\IconsDark” and “C:\Users\AppData\Local\Autodesk\3dsMax\2016 - 64bit\ENU\usericons” but keep without working.

I´ve followed this tutorial: https://www.youtube.com/watch?v=zq4C-AHrMpo

Do someone know waht I´m doing wrong?

Please, help! Thank you very much!