K20D and expanded dynamic range

My K20 arrived this week and I'm very impressed. One of the features I'm wondering about is the possibility to expand the dynamic range of the shot. The manual doesn't state the opposite specifically, but does this work on RAW images as well? Do you have experience with it and under what circumstances do you use it?

I've just started to use the D-Range as in the recent review in Amateur Photographer on the K20 they suggested that those of us using JPEG shoooting at ISO 400 and below may benefit from it being left on, no mention of RAW at all.
So I use it based on the advice above and can't say that I notice any noticeable difference, not yet anyway. I tend to use lower shutter speeds for action shots to show movement.
If you're interested the review was in the 27th September issue if you can still get a back issue.
Hope this helps,
Rob

In some other forums I read that Pentax has confirmed that it can bring out some noise in the shadows when used on the higher ISO values. No direct reference to a document/page on the Pentax webpages that I could find though.
I wish Pentax documented what the function actually does so we get a better understanding of it; the manual merely describes how to enable or disable it.