Missing X-Spam-* headers from received mail

[Chris Lajoie]

Hi, I have amavisd set up and working fine for the most part, but I am having a problem that I'm guessing is probably a configuration issue.
The X-Spam-* headers are missing from all mail that lands in my inbox. I first noticed the problem when looking at some spam that made it through... I wanted to look at the spam score of these emails, but the header is not there.
I can see the emails in my quarantine have these headers on them, but if I release one, the headers are gone when it arrives in my inbox. I currently have sa_tag_level set to 0.1.

What setting governs whether these headers are passed on?

Chris