Arno, 

"Arno Trautmann" <[log in to unmask]>, 03.01.2011 11:04:20:
> Yes, but I wanted it just for this very special thing. I hoped that it
> would be possible with some TeX-trickery or so …

if it is for a special recent purpose of yours, not for LaTeX3, 
please post that task on texhax, maybe something I have made 
earlier could help.

Cheers, 

    Uwe.