First make a backup from menu.ml in case something goes wrong. Open the menu.ml with a simple text editor like Notepad. Search for
Code:
<element id="Camera">
. In next line change the
Code:
<label type="name" textid="MENU_CAMI_TXT"/>
to
Code:
<label type="name"><text>Cybershot(you will see this instead of Camera)</text></label>
.