You can use the IIsCustomLogModule object to configure custom logging information fields. For more information about custom logging fields, see Setting Metabase Properties for Logging.
IIS://MachineName/Logging/CustomLogging
IIS://MachineName/Logging/CustomLogging/Field
IIS://MachineName/Logging/CustomLogging/FieldGroup
IIS://MachineName/Logging/CustomLogging/FieldGroup/Field
where MachineName can be any name or "LocalHost."
varReturn = object.Method
| ADSI Object Properties | 
| LogCustomPropertyDataType | LogCustomPropertyMask | 
| LogCustomPropertyHeader | LogCustomPropertyName | 
| LogCustomPropertyID | LogCustomPropertyServicesString | 
| ADSI Object Methods | Standard methods for ADSI objects. |