about diff paths

> Hi
>
> I want to know the path from a given point in a path
> for example
>
> '/Users/ducasse/Workspace/FirstCircle/MyBooks/Bk-Writing/PharoBooks/Booklet-AMiniSchemeInPharo/Chapters/Scheme.pillar'
> asFileReference path
> relativeToPath: (Path /
> '/Users/ducasse/Workspace/FirstCircle/MyBooks/Bk-Writing/PharoBooks/Booklet-AMiniSchemeInPharo/')
>
> should give me 'Chapters/Scheme.pillar'
>
> as in the example in the method
>
> (Path / 'griffle' / 'plonk' / 'nurp')
>    relativeToPath: (Path / 'griffle')
>       returns  plonk/nurp
>
> But I got
>
>  Path * '..' / 'Users' / 'ducasse' / 'Workspace' / 'FirstCircle' /
> 'MyBooks' / 'Bk-Writing' / 'PharoBooks' / 'Booklet-AMiniSchemeInPharo'
> / 'Chapters' / 'Scheme.pillar'
>
> and I do not understand. I can do it doing string manipulation but it defeats
> the purpose to have a nice library.
>
> Any hints?
>
> Stef