Hello Surakiat,
I think WrapupReasons is a new feature with SDK for HiPath 7.0
I have not used WrapUp Reason yet but I think it can be used as a reason for methods like Unavailable, etc.
But note that the only object that has implemented the IWrapupReason interface is EmailDiscardReasonKey as seen in the SDK Programming Guide documentation.
So it may be a feature that should be used only in email functionalities not in voice applications within SDK.
By the way, what kind of applications are you developing using the SDK?
You know it is not very common to find developers around using the HiPath ProCenter SDK.