How do you overwrite system/rom files such as the ringers?

[smokemojo20]

I just got a PPC6700 for my new job and am trying to copy the crossbow sounds and the vista splash screen that were posted on here. It will not let me cause they are read only. I tried Total Command and can't figure it out. I tried to install various PHM apps via activesync but must be doing something wrong as when it comes up it is not listed as a program to install.

I installed the trial version of Resco too and can't seem to get it to overwrite the files.

I have search high and low for step by step on doing this all over the internet and can't find anything. Can someone give some step by steps on how to overwrite these files?

Thanks in advance.