TLS running :-) problem with certificate

[JOYDEEP]

Dear list,

I have followed Rudy's Suggestion and TLS is working.

I have run     *imtest -t ""  linux.kolkatainfoservices.in*  and
following is the result

S: * OK linux.kolkatainfoservices.in Cyrus IMAP4 v2.2.12 server ready
C: C01 CAPABILITY
S: * CAPABILITY IMAP4 IMAP4rev1 ACL QUOTA LITERAL+ MAILBOX-REFERRALS
NAMESPACE UIDPLUS ID NO_ATOMIC_RENAME UNSELECT CHILDREN MULTIAPPEND
BINARY SORT THREAD=ORDEREDSUBJECT THREAD=REFERENCES ANNOTATEMORE IDLE
STARTTLS X-NETSCAPE
S: C01 OK Completed
C: S01 STARTTLS
S: S01 OK Begin TLS negotiation now
verify error:num=19:self signed certificate in certificate chain
verify error:num=24:invalid CA certificate
verify error:num=26:unsupported certificate purpose
TLS connection established: TLSv1 with cipher AES256-SHA (256/256 bits)
C: C01 CAPABILITY
S: * CAPABILITY IMAP4 IMAP4rev1 ACL QUOTA LITERAL+ MAILBOX-REFERRALS
NAMESPACE UIDPLUS ID NO_ATOMIC_RENAME UNSELECT CHILDREN MULTIAPPEND
BINARY SORT THREAD=ORDEREDSUBJECT THREAD=REFERENCES ANNOTATEMORE IDLE
AUTH=LOGIN AUTH=PLAIN SASL-IR X-NETSCAPE
S: C01 OK Completed
C: A01 AUTHENTICATE LOGIN
S: + VXNlcm5hbWU6
Please enter your password:
C: cm9vdA==
S: + UGFzc3dvcmQ6
C: a29sa2F0YQ==
S: A01 OK Success (tls protection)
Authenticated.
Security strength factor: 256


But from the above you can see the problem with self signed certificate.
So how can I still work with self signed CA ?

thanks