[boost] [asio] How to write custom async event provider

Hi, I'm very impressed with Asio library proposal. What I'm missing is a description (or even tutorial) about creating custom asynchronous providers. I have an object which don't sends events, but I have to ask it for events. I have to create a thread for for this task. What I want to do is an Asio wrapper for this object that will create the worker thread behind and will dispatch events through Asio demuxer. Can you point to an documentation, example or something what will help me? Thank you in advance. Regards, Vaclav