Attempting to Silence Omnia Alarms- Help!

[skrump]

I've finally sat down and am making the attempt to silence the super annoying "Charge complete" and "Low Battery" alarms on my Omnia. The technique I'm trying is to record the sound of blank silence, and swap the "Blank silence" file of my own creation out with the corresponding sound files in the Windows directory. The Format is Wma, I've got my blank file recorded, and am good to go, but here's where I hit the wall- The sound files in the windows folder of my Omnia are listed as "Read Only". Which means I can't delete, move, rename them, anything. This just drives me up the wall, when the devices I've purchased smugly tell me I'm not authorized to change them. I tried unchecking the "Read Only" box in the properties menu for each file, to no avail. Any help would be appreciated! I think the applicable files I'm trying to tweak are:
Lowbatt.wma
Notify.wma (Found a wav version of this file as well..???)
Alarm2.wav

Thanks in Advance!!