[Dovecot] checkpassword memory limit

[a]

Hi. I am trying to authenticate dovecot from a wordpress database. I was thinking of using the checkpassword script to start a cli php script. That php script would then include the necessary wordpress functions, do the auth (find the wp username from user database using the email address, and authenticate with the user/pass), and return the result to the checkpassword script. I made the above scripts (the php script will be used to authenticate some other services too), and when I run them "by hand" (even with "sudo -u dovecot ..."), it works. But, when the dovecot runs them, the php runs out of memory. After a lot of debuging, I find out that when the dovecot starts the checkpassword script, it makes a 250kB memory limit. But it is not enough for the php script, it needs 14MB. I tried to put a "ulimit -v 16777216" into the checkpassword.sh, but it doesn't work.Is there some hardcoded limit in the dovecot itself? And if there is, could it be somehow changed?I am using a simple D
 ebian Wheezy LAMP, and installed everything from repo. Thanks for every idea.