You send a meeting request to the resource mailbox. The meeting request is declined.
In this scenario, the response details are still included in the response email message.
Additionally, if the AddAdditionalResponse property is set to True, the text that is specified in the AdditionalText parameter are not included in the response email message when the EnableResponseDetails property is set to False.
To resolve this issue, install the following update rollup:
2407025 Description of Update Rollup 2 for Exchange Server 2007 Service Pack 3
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
For more information about automatic booking on a resource mailbox, visit the following Microsoft website: