I'm stuck with the following problem at the moment:
In a Catalyst Controller I get a result that is a Bio::Seq object, which is an object containing biological sequence data and additional information about the sequence but it could be any other object, really.
In my views, I can then show a textual representation of the object, for example a Bio::Seq object has a 'seq' method that returns the actual sequence string (AGCAACG...), so in my (TT) view, I can have:

The sequence is:[% bio_seq.seq %]
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where $c->stash->{bio_seq} was populated with a Bio::Seq object in the controller. So far so good...

What I would now want to do is to use the information that comes with the Bio::Seq object to render a more informative version of it, which should use styles to highlight some sequence features. Basically, I would like a view helper method that takes the Bio::Seq object as an argument and returns a snippet of HTML with the sequence and style information to insert into the view. I know how to use TT FILTERs but they wouldn't work with the object, so I found the 'expose_methods' config option in Catalyst::View::TT, which sound like just the ticket but I'm not having any luck with it.
In MyApp::Controller::BioSeq.pm

sub bioseq :Global {  
  my ( $self, $c ) = @_;
  my $bio_seq_obj = Bio::Seq->new();
  # ... a lot of stuff, finally this:
  $c->{stash}{bio_seq} = $bio_seq_obj;
}
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In MyApp::View::TT (just a silly example that would return a static text just to see if it works)

__PACKAGE__->config(
    # some config ...
    expose_methods => [qw/colorised_seq_features/],
);

# for testing purposes
sub colorised_seq_features {
  return 'testing, testing, 1,2';
} 
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And in the template file that is rendered in the end:

The sequence is: [% colorised_seq_features(bio_seq) %]
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But colorised_seq_features simply renders nothing and there is no error message either (I did turn on DEBUG in the View::TT config).
I tried to use a method name that definitely doesn't exist and the view still doesn't complain, so I'm not sure where thie is going wrong.
Does anybody have any experience with expose_methods? The documentation is very short and I can't find much else about it. I have used similar techniques (view helpers) in Ruby on Rails and I was hoping to use the same technique in Catalyst. Am I completely on the wrong tracks (excuse the pun...)? I should also mention that I could of course do all of this in the controller and populate the stash with a HTML snippet but I would like to use the same technique in different views and I really think that the controller shouldn't provide HTML snippets and let the view sort that out.
Thanks for your help!