layers and papersize

[Tom Fossen <tom.fossen@xs4all.nl>]

This is probably a beginners question. While trying to understand the 
layer-mechanism I made a drawing which is meant as a background for a 
schedule in a magazine. I add the information within this drawing using the 
'register' option I found on page 263 of the Metafun manual.

Here is the example in a minimal form:
 
\starttext
\definelayer[rooster]
\startuseMPgraphic{list}
	path p, s ;
	p := unitsquare  scaled 3cm superellipsed 0.84 ;
	s := flex ((2.5cm,3.0cm), (10.0cm,3.0cm), (6.5cm,-0.5cm)) ;
	draw p withpen pencircle scaled 5pt withcolor .625white ;
	draw s withpen pencircle scaled 3pt withcolor .625white ;
	register ("da",2.4cm,2.4cm,(.3cm,2.8cm)) ;
	register ("name",5.6cm,0.6cm,(5.4cm,3.5cm)) ;
	register ("who",6cm,3cm,(3.4cm,2.8cm)) ;
	register("color",1.5cm,0.5cm,(7.6cm,-0.6cm)) ;
\stopuseMPgraphic

\setMPlayer[rooster][da]{\framed	
[width=\MPlayerwidth,height=\MPlayerheight,align=right] {pos 1}}
\setPlayer[rooster][name]{\framed 
[ [width=\MPlayerwidth,height=\MPlayerheight] {pos 2}}
\setMPlayer[rooster][who]{\framed 
[width=\MPlayerwidth,height=\MPlayerheight,align=right] {pos 3}}
\setMPlayer[rooster][color]{\framed 
[width=\MPlayerwidth,height=\MPlayerheight] {pos 4}}

\getMPlayer[rooster] {\useMPgraphic{list}}
\stoptext

This works for the standard papersize. But I want this to work in a magazine 
on A5. So I add:

\setuppapersize [A5][A4]
\setuparranging [2UP,rotated,doublesided]
\setuppagenumbering[alternative=doublesided]
\setuplayout[margin=0pt,width=middle]

followed by the fragment above.

But now all of the texts ("pos x") end up somewhere in the left corner of the 
page. Only the drawing is on its right place. I tried to experiment with 
adding 'position= on' or 'off' to the 'definelayer' command. No difference.

Where are the misunderstandings on my side?

												tom fossen