[CentOS] dovecot + pigeonhole on CentOS-7

I've everything running fine under CentOS-7, as far as I can tell,
except that spam is not being diverted to my spam folder
~/Maildir/.Spam .
I'm running postfix + spamass-milter + spamass-milter-postfix + dovecot
(+ spamassassin), and spam is being duly marked
before ending in my inbox .

As far as I can see, the current advice is to leave filtering
to dovecot, using the dovecot-pigeonhole rpm.

I'm wondering if anyone else is doing this?
If so, what settings exactly did you use?
I haven't been able to find any clear documentation,
or rather I have seen widely differing instructions.
My brief attempt failed, so if anyone can help
I should be very grateful.

(Or if anyone has a better spam filtering scheme ...)



-- 
Timothy Murphy  
e-mail: gayleard /at/ eircom.net
School of Mathematics, Trinity College, Dublin 2, Ireland