trying to index comments with acts_as_ferret and acts_as_commentable

i have a model that is commentable. I want to index the comments with
ferret like so:

acts_as_commentable
acts_as_ferret :fields =>
[:title, :tag_list, :description, :pseudo, :assetcomment]
def assetcomment
   self.comments.each { |c|
     comment << c.comment
    }
    return comment
end

it won't index anything.

If however, I change to:
def assetcomment
  return self.comments[0].comment
end

it will index the first comment.
I've deleted the index folder and so on...

I've been going circles and googling for a while on this, any advice
would be much appreciated...