sieve: fileinto and keep

[Walter Steiner]

I have a problem with fileinto/keep/duplim

sieve script:

elsif envelope :localpart :is "to" "ws+test" {
        fileinto "INBOX.test";
        keep;
}

(-- end of script --)

Messages addressed to ws+test are saved into INBOX.test
but there is no copy in my INBOX as expected.

lmtpd[21763]: [ID 538540 local6.info] dupelim: eliminated duplicate message to 
user.ws.test id <messag-id>

"to user user.ws.test" - nothing to do with the missing copy in INBOX?

anyhow, how to keep a copy in inbox and in a special folder?
(procmail c flag)

cyrus-imapd 2.0.9 Solaris 8

Thanks in advance, ws