[Dovecot] plugin cmusieve not found

[juan carlos]

I have debian lenny and dovecot 1.2.4 and a problem with the plugin cmusieve.
protocol lda {
  postmaster_address = postmaster at cablenet.com.pe
  mail_plugins = cmusieve quota
  log_path = /var/log/dovecot-deliver.log
  info_log_path = /var/log/dovecot-deliver.log
}

the log /var/log/dovecot-deliver.log shows me the following
Fatal: Plugin cmusieve not found from directory /usr/lib/dovecot/modules/lda

When I list the directory /usr/lib/dovecot/modules/lda, it was not found the
cmusieve plugin. Where can i get it?

# ls -l /usr/lib/dovecot/modules/lda
lrwxrwxrwx 1 root root 22 nov 12 21:20 lib01_acl_plugin.so
lrwxrwxrwx 1 root root 24 nov 12 21:20 lib10_quota_plugin.so
lrwxrwxrwx 1 root root 24 nov 12 21:20 lib11_trash_plugin.so
lrwxrwxrwx 1 root root 29 nov 12 21:20 lib20_autocreate_plugin.so
lrwxrwxrwx 1 root root 26 nov 12 21:20 lib20_convert_plugin.so
lrwxrwxrwx 1 root root 25 nov 12 21:20 lib20_expire_plugin.so
lrwxrwxrwx 1 root root 22 nov 12 21:20 lib20_fts_plugin.so
lrwxrwxrwx 1 root root 29 nov 12 21:20 lib20_listescape_plugin.so
lrwxrwxrwx 1 root root 27 nov 12 21:20 lib20_mail_log_plugin.so
lrwxrwxrwx 1 root root 26 nov 12 21:20 lib20_virtual_plugin.so
lrwxrwxrwx 1 root root 28 nov 12 21:20 lib21_fts_squat_plugin.so
-rw-r--r-- 1 root root 3663976 nov 15 23:04 lib90_sieve_plugin.a
-rwxr-xr-x 1 root root    1029 nov 15 23:04 lib90_sieve_plugin.la
-rwxr-xr-x 1 root root 1777465 nov 15 23:04 lib90_sieve_plugin.so