Any code generated specialized interface will automatically get .NET properties created that will provide shortcuts to the actual property on the interface. An example of this is the SPFReasonForCancel property on the ISPFTransmittal interface.
Typically this could be accessed in the following way,
Me.SPFReasonForCancel
or by going to the interface directly to access:
Me.Interfaces("ISPFTransmittal").Properties("SPFReasonForCancel").Value