[Catalyst] newbie yaml question

[Eric W. Bates]

I'm a little vague on the use of YAML for the all the config options; 
but I have my Template Toolkit options in there:

# TT config options
View::TT:
   CATALYST_VAR: c
   INCLUDE_PATH:
     - /usr/local/www/HG/root/src
     - /usr/local/www/HG/root/lib
   PRE_PROCESS: config/main.tt
   WRAPPER: site/wrapper.tt
   ERROR: errors/error_msg.tt
   TIMER: 0
   PRE_CHOMP: 1
   COMPILE_EXT: .ttc
   COMPILE_DIR: /var/spool/tt_compile
   FILTERS:
     bloom_sequence: \&HG::View::TT::format_bloom_sequence

All of it works except for the FILTER definitions.  When I use the 
above, I get the error:

filter error - invalid FILTER entry for 'bloom_sequence' (not a CODE ref)

How do I specify a code ref in YAML?

If it's not possible can I use both the YAML and the traditional 
'config()' method?  (I do question whether using 2 separate methods in 2 
separate files to perform a single config is really transparent...)

Thanks.