How to easily use another skin?

Based on example 4,

I tried to directly change the used skin in my php code, not in the config js file.

Unfortunately, this doesn't work:
$oFCKeditor->Config['SkinPath'] = "editor/skins/office2003/" ;

in the example, it says:
$oFCKeditor->Config['SkinPath'] = $sBasePath . 'editor/skins/' . $_GET['Skin'] . '/' ;

which should be the same imho.

any ideas why this doesn't work???