[Exim] How to add X-Filtered-Bulk to messages ?

I made a complex regexp for subject and want to add header line
"X-Filtered-Bulk: Yes" to messages, where subject matches.
Message MUST proceed to their destination, fail not needed.

Second question: how to make ignore case regexp's without annoying
[Aa][Dd][Uu][Ll][Tt] (in system_filter) ?