Math startarray and \cases{xxx} bug?

[Maurice Diamantini <Maurice.Diamantini@ensta.fr>]

Bonjour à tous,

I'm using amsl module, but it seems there is a probleme
with the startarray/stoparray environment which apear with the "t"
type of column (t for text).
So the basic cases commande doesn't work.

Also the \startcases/stopcases should have the same meaning thas
\cases{xxx} has, but it doen't.

I use textlive distrib with a copy og t-amsl.tex version 2004.11.18

Thank you for any help!
-- Maurice Diamantini

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\usemodule[amsl]
\starttext

\startformula
     {\bf f(x)} =
     \cases{
         \sum_{x=1}^n x      & if I am false
         \\
         \displaystyle% just to see the difference
         \sum_{x=1}^n x^2    & \text{if I am true}
    }
\stopformula

% This formala works as expected, but if I replace
% the forth column of type "l" which contains some \text{xxx} stuffs
% with a column of type "t" without using the \text command,
% there is an error.
\startformula
     {\bf e_u(t)} =
     \left\{
     \startarray{dlll}% ou bien : \startarray{| d | l | r | l}
         \displaystyle
         \sum_{x=1}^n f(x)
             & = ax^2 + b.x + c,
             & = a
             & \text{Here some text}
             \\
         \hfil y_2    % just to center stuff within a "d" column
             & = 3ax^3 + 3ax^2 + b.x + c,
             & = b
             &
             \\
         \sum_{x=1}^n h(x)
             & = y_2,
             & = a + b
             &  \text{encore du $(x^2)$ texte}
     \stoparray
     \right.
\stopformula

\startformula
     {\bf e_u(t)} =
     \startcases
         \sum_{x=1}^n f(x)
             & if I am true
         \\
         \displaystyle
         \sum_{x=1}^n h(x)
             & if I am false
     \stopcases
\stopformula
\stoptext