DGoldman blogged a very important info about generation of warning (9359) on Exchange 2010 servers whenever you attempt to generate the OAB. The warning is:

Log Name:    Application
Source:          MSExchangeSA
Date:              12/1/2009 13:01:03 AM
Event ID:        9359
Level:             Warning
User:              N/A
Computer:     OABGenServer
Description:   OALGen truncated or dropped properties for entry ‘Dgoldman’ in address list '\Global Address List' because they exceeded the configured size limits for the version 4 offline address list.  The affected MAPI ids are:  8008. - \Default Offline Address Book

And the full article is here http://blogs.msdn.com/dgoldman/archive/2009/12/01/please-read-events-9320-and-9359-on-new-installation-of-exchange-2010.aspx