System Buttons bug or rule ?

hi, i have skin and substyle and i use Skin Studio 5 problem is that in both main skin and substyle i made new system buttons and SkinStudio 5 in both skins sees and shows my new buttons but window blinds 6 (6.02) only skins new buttons in substyle and refuses to skin new buttons in main skin reason i dont know... is there some rule to this or is it a bug ? just to note that substyle is cloned from main skin so i realy dont understand why substyle gets new buttons and main skin not when they are actualy from the same template