i've a content type article, where user can create new terms to a vocabulary through free-tagging. Now I'd like to provide the new created term also to be available in my forum, so user can discuss about this terms in the forum. I've assigned the vocabulary to my article and to my forum. But that alone does not work the way, I'd like to. Can anybody please help me to get this working? Please also let me know, if the problem is not getting clear to you. Thanx for your suggestions.

I've a content type article, where user can create new terms to a vocabulary through free-tagging for example content, color and so on . When the user creates a new content, he can add new terms to the categories. Now I'd like to provide the new created terms also to be available in my forum vocabulary, so user can discuss about this terms in the forum. I've assigned the vocabulary to my article and to my forum. But that alone does not work the way, I'd like to. In the meanwhile I'm using the Taxonomy Manager for just copying the terms from the 'article' vocabulary to the 'forum' vocabulary. But that's not the best solution for me, cause I've to manually do this for every added term. It would be great, if this could happened 'on the fly', some kind of automatically.
Can anybody please help me to get this working? Please also let me know, if the problem is not getting clear to you. Thanx for your suggestions.