If you want to replace the chat window background you can search this in you 920 style:
quote:
Element[ID=Atom(ai93)]
{
Background:rcbkd(20061);
}
... and replace th original background with your custom picture, like this:
quote:
Element[ID=Atom(ai93)]
{
Background:rcbkd(59127);
}
... of course use your image id.
hope this helps dude