You need to remove two files from Video directory
"kb-startlogo_alpha.bik"
"kb-startlogo-add.bik" (those two i belive)
and modify the file
"Start_KBlogo_eng.png" from loc_data directory
A sample here :
http://img171.imageshack.us/i/mainscreen.jpg/
My mage char it's a woman (armored princess import) and looks just like here so the background makes sense
