[Exim] How do you handle dead clams?

Exim 4.30/exican-acl - FreeBSD 4.8 - clamav/clamd 0.65

clamd dies every so often which causes my users to get a 451.

Is there any way to make exim just queue the email when clamd isn't running?
Or maybe even skip the clamd DATA ACL when clamd isn't running?

Elliot