[Q] (newbie) typesetting layer to column

["Rolf Marvin B e Lindgren" <r.m.b.lindgren@usit.uio.no>]

I'm giving ConTeXt  a first go in typesetting a diploma.  

I've figured out that I'd like to try to typeset to a five-column grid.

Most of the stuff should be centered against the third column, while
some stuff should be centered to the second and fourth column.

This makes for a very boring diploma, but that's beside the point at
this stage.

I want 1-inch borders throughout, so before \starttext, I have 

\setuplayout[paperheight=29.97cm,paperwidth=21cm,leftmargin=1cm,rightmargin=1cm,header=1cm,footer=1cm,textwidth=19cm,textheight=27.97cm]

(I pretend that marginpars don't exist.  I'm sure they'll come back and
haunt me).

Furthermore, before \starttext, I set up the layers I think I need with

\setuplayout[grid=yes,columndistance=12pt,columns=5]\showgrid
\definelayer [text] 
\setupbackgrounds [text] [background=text]

(The showgrid is there because I like to see what I'm doing).  Then I
have, say,

\setlayer[text][column=3,line=7]{Diploma awarded to}

what do I say in order to have the text centered relative to the
column?  

and on a sitenote,

I'd like to have a frame around the entire page.  Preferably, I'd like
to be able to place it using numerical coordinates (absolute or
relative, set to a layer or not).  Is this, or something close to it,
possible? 

thank you,

-- 
Rolf Lindgren                                            http://www.roffe.com/
roffe@tag.uio.no