imapsieve pigeonhole plugin?

[Larry Rosenman]

How do you enable the imapsieve plugin?  I added
sieve_plugins = imapsieve

and it whines:
hebighonker.lerctr.org /usr/local/etc/dovecot/conf.d # service dovecot
restart
managesieve: Fatal: Plugin 'imapsieve' not found from directory
/usr/local/lib/dovecot/sieve
doveconf: Error: managesieve-login: dump-capability process returned 89
Stopping dovecot.
Waiting for PIDS: 97491.
managesieve: Fatal: Plugin 'imapsieve' not found from directory
/usr/local/lib/dovecot/sieve
doveconf: Error: managesieve-login: dump-capability process returned 89
Starting dovecot.
managesieve: Fatal: Plugin 'imapsieve' not found from directory
/usr/local/lib/dovecot/sieve
doveconf: Error: managesieve-login: dump-capability process returned 89


this plugin seems to be poorly documented. :(

-- 
Larry Rosenman                     http://www.lerctr.org/~ler
Phone: +1 214-642-9640 (c)     E-Mail: larryrtx at gmail.com
US Mail: 17716 Limpia Crk, Round Rock, TX 78664-7281