How to disable the IMAP storage feature of app_voicemail?

Hi,

I have already been using the Debian unstable package of Asterisk for half an year ago. The default binary did not contain IMAP storage feature until now.

The latest version I installed is 1.4.11~dfsg-3, which the default binary has the IMAP storage feature compiled-in. When I start up my asterisk, it shows a lot of warning every few seconds as follows :

WARNING[15539] app_voicemail.c: IMAP user not set for mailbox XXX.

I want to disable the IMAP storage temporarily and not to show these warnings before my imap server is changed from courier to dovecot.

Thanks in advance.