I have a blog post on this subject that talks about implementing a menu item that is specific to a custom list/document that the feature is also creating at http://sharepointinsight.com/blog/Lists/Posts/Post.aspx?ID=33. I hope this will help you. Also if you're having trouble getting the {ListId} token to work (you're getting an error stating that the list does not exist) check out this post which should help as well. http://sharepointinsight.com/blog/Lists/Posts/Post.aspx?ID=32