Found the solution to all theme issues/problems for all blackberries
The reason why ALL themes fail in the task of having an "updatable" homescreen for weather app icons and other icon (sms/mms, messages ...etc) is because of the homescreen itself... The homescreen is just an static shell(hence why you have to press menu or move the trackball to update), the real "auto-updatable" screen is the "application screen" in order to have the icons update automatically (like the dimension icon theme) is to create a theme WITHOUT a homescreen... just a straight forward application screen as your front.
Get an old curve/pearl and put the dimension icon theme put the backlight to 2 minutes and then put the weather app to update to the most frequent setting and you will seee that icon automatically change (like the network reception bars)