Check out the below links for info direct from HDS on the Zero Page Reclaim feature that works with Dynamic Provisioning as of ucode 60-04-04 on the USP V -
Webex playback - requires registration
If the above pages move, you can see all publically available WebTech sessions from www.hds.com/webtech
On the Webex session there is also mention of the anticipated availability of being able to dynamically re-balance page distribution within a Pool. This is another feature that lots of people have talked to me about, basically when adding more capacity to an existing Pool will the Page layout be re-balanced (levelled) over all of the existing AND new capacity. The answer at the moment is No, but it sounds increasingly like this feature will hit the streets later this year.
Hopefully this may lead to the ability to migrate at the Page level via HTSM? Pure speculation on my behalf.