diplayed centered equations

[olivier Turlier <crp.tbeb@wanadoo.fr>]

hi contexers

I'm having pb trying to arrange aligned centered equations. When 
compiling for right %\eqalignno or left %\leqalign, no pb's. But contex 
is'n t happy with centered ones %\eqalign. Don't know how to solve this 
tiny  but irritating pb.
Here a minimal exemple :

%working
	\placeformula[form:a-prime]
         \startformula
             a^{'} = \frac{1,05 \times N_{s}}{q_{s}} = \frac{1,05 
\times 			0,246}{0,15} = 1,722  \approx \inframed{1,75 m}
         \stopformula

%working
	\placeformula[form:a-prime]
	\startformula
	 \eqalignno{ %%or \leqalignno%%
  		a^{'} & = &  \frac{1,05 \times N_{s}}{q_{s}} 
\formulanumber[form:a-prime:a]{a} \cr
  		 & = &  \frac{1,05 \times 			0,246}{0,15} 
\formulanumber[form:a-prime:b]{b} \cr
		 & = &  1,722  \approx \inframed{1,75 m} 
\formulanumber[form:a-prime:c]{c} \cr
	} \stopformula
	

%not working
	\placeformula[form:a-prime]
	\startformula
	 \eqalign{ %%or \leqalignno%%
  		a^{'} & = &  \frac{1,05 \times N_{s}}{q_{s}} 
\formulanumber[form:a-prime:a]{a} \cr
  		 & = &  \frac{1,05 \times 			0,246}{0,15} 
\formulanumber[form:a-prime:b]{b} \cr
		 & = &  1,722  \approx \inframed{1,75 m} 
\formulanumber[form:a-prime:c]{c} \cr
	} \stopformula




%not working
	\usemodule[nath]
	\placeformula
		\startgather
  			f(x) = x   \\
  			g(x) = x2 \\
  			h(x) = x3
		\stopgather
	\stopformula

Thanks for the answer

Olivier