The BUTTON keyword defines a button that executes a macro.
The function must have the following parameters and visibility:
Public Function routinename(ByVal strPropName As String, ByVal lngDDID As Long, ByVal strPrevValue As String, ByVal strValue As String, ByRef varRet As Variant) As Long
•strValue is the current value.
•varRet receives the value to be written to the property identified by the TARGETPROP keyword, which is optional.