When trying to set the External addresses for the Group Expansion Server, The Address Book Files and the Meeting Content Download you would normally use WBEMTEST to set the WMI parameters.

In a normal scenario, you would open each of the relevant objects e.g. MSFT_SIPAddressBookSetting, and click the "Instances" button. It seems that with OCS 2007 R2 you can't do that. You get an error like the following;

Number: 0x80041024

Facility: WMI

Description: Provider is not capable of the attempted operation

Instead of doing that, you have to do a query for any instances and in particular, you have to specify "where backend=xxxx" as part of the query. So for example if you have an Enterprise pool with SQL installed as the default instance, the query would be as follows;

select * from MSFT_SIPAddressBookSetting where backend="mysqlserver"

Detailed information on this is provided in the following Microsoft Support Article (http://support.microsoft.com/kb/938288).