Ok, this property is not exposed in 98 or 2000, only in OL 2002. The property name is MAPIFolder.ShowAsOutlookAB.

There might be a way to do it with CDO, but don't know for sure. See http://www.cdolive.com/cdo10.htm under "Folder properties" for info on this.

>Thanks for your answer !
>Is not the DefaultItemType property. In the Outlook-Application i mark
>a own Contact-Book to use as Email-Addressbook. If this Checkbox is
>not set, the Email-Address from the Contact-Entrys are not show in Emails.
>Im not found the Property to set this Checkbox via OLE.
>
>Hendrick
>
>
>>>Hi,
>>>
>>>I'm seek the Outlook(>98)-Property to mark a Contact-Folder as Email-Adressbook.
>>>
>>>Hendrick Kurland
>>
>>Have you looked at the DefaultItemType property of the folder object?