What's the proper procedure for releasing emails caught in amavisd's quarantine in zimbra?

I had a look at amavisd's documentation and it mentions a amavisd-release, but this util is not present in the zimbra package.

Manually copying the file does not seem to be the proper solution either. amavisd saves the entire email, not just the attachment.

I don't know of any attachment extracting utils, as I generally deal with windows not linux.