If you are talking about the weather tab on the standard htc home then the only thing that might allow changes like this would be HTC Home Customizer but I really don't think it would make a change like that. You would probably have to extract htc home and edit the program somehow. If I were you I would just install Weatherpanel and make it one of the shortcuts on the launcher tab. Now, if you are talking about Manila 2d which is like Touchflo3d on the TouchPro or Diamond then I remember reading somewhere that users integrated Weatherpanel somehow.If you flash to a custom rom that has manila 2d on it then you might be able to do what those Touchflo3d users did.
