Urgent acts_as_tree attributes

Hello, I have a class "ve" which acts_as_tree and has an attribute "recommendations", which is itself another model (referenced by a belongs_to, has_many relationship, a "ve" has many recommendations)

I wish I could get all recommendations for a specific node, knowing that this number would be the sum of its own recommendations and those of its children, and it's children's children and so on.

I think the best wat to do it is through a helper, but I get stuck wit the algorithm. For exemple, if I want only to get the sum of all recommendations present, it's easy throgh the folowing helper (which even might be more performant, i guess)

def get_recommandations_number(node, ret)     if node.has_children?       for n in node.children         ret = get_recommandations_number(n, ret)       end     end     ret += node.recommendations.count end

However, being recommendations another model, I can't get it through the same algorithm.

I hope there's an easy way, but I am not very good with ruby.

Would anybody please help me?