centered text by the right side

hello

i would want to see a new feature to leave us the choice the position of text

exemple: username it placed here on the right side of menu but if i want it in the good place in need to give a rule into .xml file but it works only for my user name (7 letters) , with looooong username it gives a wrong position cause the position is ruled by le left side (wich is normal) maybe as in html files we can hav the pixel or % way to put Label

i hope it's understandable

attachment screenshot gnomemenu and username Label
http://dl.dropbox.com/u/187396/screenshot1.png