the code now looks like this:
-moz-border-radius:8px 8px 8px 8px;
border: 6px solid #899092;
padding: 6px 6px 6px 6px;
i had to add width, because the right border was 100px to the right of the content...
anyway, great work, and thanks a lot for your help.
i hope this will help others as well.