To change this you have to edit the system/usr/keylayout/vendor_0001_product_0001_kl file.
In this file you will find key numbers with matching function. Change the function to the desired one.
key 115 VOLUME_UP into key 115 VOLUME_DOWN
key 114 VOLUME_DOWN into key 114 VOLUME_UP
You can also change the function of the home button - key102 HOME - into back or power.
Edited by PiotrJakub, 18 October 2012 - 04:01 AM.