changing menu background

[Guest kendon]

i want to change the menu background of the senseui menu. for starters back to the original android background, but anything is possible... :(

does anybody know how to do this? i am able to handle apks as i roughly understand their structure and figured out how to sign them :) but i don't know where i can find the background file... i guess/hope it is a simple .png somewhere, any ideas?