problems with step and stepwise

In a presentation I need three steps on one foil and some letters to =
be
seen and to be hidden:

Seen in
step 1: A, B, C
step 2: A, B, C, D, E
step 3: A, B,    D,    F, G, H, I

I try to get this result with the following code, but it fails showin=
g C
in step 1 and D in step 2. What is wrong?

\documentclass
[calcdimensions,landscape,letterpaper,KOMA,final]{powersem}

\usepackage[lightbackground,display]{texpower}
\usepackage{tpslifonts}
\usepackage{pstricks}

\begin{document}



\begin{slide}
    \stepwise*{
      \psset{%
        xunit=3D0.75cm,
        yunit=3D0.75cm,
        runit=3D0.75cm
      }
      \tiny
      \begin{pspicture}(0,0)(12,9)=20
          \rput(0.0, 8){A -- always visible}
          \rput(4,5){B -- always visible}
          \step[\value{step}=3D1][\value{step}=3D2]{%
            \rput(2., 6.5){C -- visible in step 1 and 2} }

          \step[\value{step}=3D2][\value{step}=3D2]{%
            \rput(5.5, 6.5){E -- visible in step 2}
          }

          \step[\value{step}=3D2][\value{step}=3D3]{%
            \rput(11,5){D -- visible in step 2 and 3}
          }

          \step[\value{step}=3D3][\value{step}=3D3]{%
            \rput(7.5,8){F -- visible in step 3}
            \rput(4,8){G -- visible in step 3}
            \rput(5.75,6.5){H -- visible in step 3}
            \rput(9.25,6.5){I -- visible in step 3}
          }
      \end{pspicture}
    }
\end{slide}

\end{document}

Many thanks for your help in advance!
--=20
Prof. Dr. Jobst Hoffmann <[email protected]>
Fachhochschule Aachen, Abt. J=C3=BClich





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