If you learned what you need to modify "systemui.xml" file, you can presumably learn what command to use. A good test for "will you screw up your system and then come here asking for help on how to fix it" is "did you find everything available on at least talk.maemo.org available on the issue already". If the latter is a yes, the former isn't always a no, but but if the latter is a no, the former is likely to be a yes.

Not to mention that you don't NEED to modify this file, you don't NEED the command to do it, and you definitely don't NEED help (the kind you're asking for anyway) if you have to ask for something this commonly stated on this forum. It's in the f'ing wiki if I remember right, which is saying something.

Search Results (for just the word "systemui.xml"). One even has "noob instructions" in the thread title:
http://talk.maemo.org/showthread.php...t=systemui.xml
http://talk.maemo.org/showthread.php...t=systemui.xml

If you don't read through at least those first posts though, and ideally skim those threads entirely, the command you need to use is:

vi [name-of-file] - which in this case means vi systemui.xml if you're in /etc/systemui already, or vi /etc/systemui/system.ui.xml

When you're in vi, you start editing by pressing "i", then press esc (it's on the X-Term's bar at the bottom) to exit editing mode. Then enter ":wq" (it'll appear at the bottom line), if you want to save it, or ":q!" if you don't want to save your changes. Press enter. You need to run this command as root. Which means either type "root" or "sudo gainroot" and press enter before entering this command, or type "sudo vi [path/file]". If that doesn't work for you, you need rootsh installed. If you can't be bothered to figure out the rest (I don't mean you have to experiment and fiddle and such. Just use the search. This topic, at least, is covered enough on the forums that you CAN find everything you need to know already) on your own, you shouldn't edit system files yet.

The command for copying is done with "cp [path and/or name of file-to-be-copied] [path of where you want to copy the file and optionally the name you want to name it]". I tell you the copy command because I hope you make a backup.