[Bro] Extract files based on magic number using Bro 2.2

[Marius Portaas Haugen]

Hi all!

I'm just wondering; Is it possible to extract files based solely on 
their magic number using Bro 2.2
In Bro 2.1, it was possible to extract files just by comparing the 
magic number
with the first X bytes. I used the script provided here, with great 
success:
http://scrapbook.zscaler.com/2012/05/bro-script-to-extract-artifacts-from.html

However, in Bro 2.2, thigs seem to have changed. Most examples and docs 
now only
seem to use the MIME-type to determine if a file will be extracted or 
not, e.g. here:
http://www.bro.org/sphinx-git/frameworks/file-analysis.html

I also see that there har been included some sort of "magic number 
database"(/bro/share/bro/magic/), but I find little
documentation on what its role is in regards of file extraction, as 
well as the formatting that is being used.

Have I missed something essential here?
If anyone could help me better understand how file extraction works now 
in Bro 2.2, it is most appreciated! :)

Best regards,
Marius P. Haugen.