For People looking where to edit Panel Asset. (the 'wrong' way.)
Okay so I have not been here all that long, but while trying to modify the core of my copy of this wonderful script i decided to search for an answer as to where to find the file to edit the theme assets.... Now if you have ever searched this you to might have been as disappointed as everyone else here to find that no one wants to divulge this info.
Regardless of their reasons I believe in sharing information and thus this is exactly what I am going to do.
To find asset coding goto library/core/class.theme.php
Now kindly before anyone decides to tell me i should not mess with this file or blah blah blah, please let me put you at ease. I know my way around PHP and OOP quite well. Thanks for your concern but it is not needed.
Let me also say that if you don't know what you are doing, and you mess it up, don't blame me. Always remeber to backup before screwing with core files, or any files really.