Newbie skin modification problem

Hi there, I've just installed Xwiki in local to try it out, and i'd like to customize the theme. Ludovic said in a (very) old post that you can create your own new skin by creating a "skins/newskin" folder next to "skins/default" folder, putting in it all the template files and css files (coming from "skins/default") that you need to modify and modifying them. Then watching the result by using "?skin=newskin" or turning it on in the preferences. So i did this way, and it works well when modifying the templates structure(ie: header.vm). But i got some trouble as soon as it uses getSkinFile() which is supposed to call the file between () with its path (am i wrong?): it always call the file from the default skin folder (while it uses the header.vm from newskin folder :/ ). So i don't manage to call my own logo or my modified style css from my "newskin" folder. Should'nt it automatically switch to newskin folder path since i use newskin skin in my preferences? Where am i wrong? I know i could modify the skin via the edit object.. and so on but i'm not comfortable with that approach and i'd prefer to be able to gather all the skin files in hard in a same folder. Thanks in advance Nicolas