When doing that trick, it does show on the theme selection but it only displays a black image with the default buttons, instead of what it should look like :/ Could you by any chance tell me what changes did you do to <Button> as well to get it to work ?
sure, i dont use the nice skin of daydream, but i took a quick look. the author took away the refference to the base skin, which can help when an element is added. when you open an other main.xml, the one from obsidian, you see what i mean in the second line. mc looks at this shared base xml file after using the one in the skin, and picks the things not defined in the main.xml.
now in this base there is an element added. the bitmap in the <ROLLER Class="Root">. this can be added to the original, and as far as i remember i used the bitmap for listselection from my own skin.
now, maybe you also want to see the background images (that is what you ment with beeing all black?).
in the main.xml you find a line:
<Item Bitmap="Pictures\ViewBackground.png" Location="***" Rect="ViewBackground\0,0,100,100" Alpha="90" Background="1" />
change the alpha value to 20 or 10.
hope my explanation is a bit clear.
gab