Hi, my name is Jaime and I come from Spain.
In our daily work as designers we use RTM to share our tasks, and we've come to an end in this topic.
As many of you might know, we need to track dates and subtasks inside a single task.

What have we done to achieve that?

Well, very simple but helpful.

We have several tags, one for each one of the stages: briefing, prototype, design, html, public

The customer tags the task as 'briefing', and shares it with our team. Once they've decided what to do, they tag it again as 'prototype' and erase the previous tag.
Our prototypers have a smart list with the tag 'prototype' so as to receive there the new tasks and so on. Once they're done, they erase the tag 'prototype' and type a new one, 'design', so the designers could receive it in his smart list.

I know it could seem a little bit strange, but is working for us.

Thanks. Bye.