[rules-users] RuleFlow: custom nodes

I am starting to evaluate RuleFlow. I would have one question: is it possible with eclipse designer to create custom node, and save its definition somehow, so that it becomes available in component panel, by some import, or update mechanism? If it is, how this can be done? My wish is to provide custom rule sets and custom work item nodes for WS invocations to the client, who will create Rule Flow by himself with enriched set of nodes. I could not find that in documentation, although I think I read it is possible somewhere. Thanks and best, Milan