There is a new IsInstantSearchEnabled Boolean property, but it's read-only.
I don't see a way offhand of setting that property on a store by store
basis, even though the read-only property is store by store.
Since the indexer is not Outlook but WDS, there wouldn't be anything in the
OUtlook object model for that. I haven't looked to see if there's a WDS 3.0
API.
--
Sue Mosher, Outlook MVP
Author of Configuring Microsoft Outlook 2003
and Microsoft Outlook Programming - Jumpstart for
Administrators, Power Users, and Developers