Hi Duncan,
In case your Service Operation Method takes a .Net Objcet as a parameter you can try setting a MIDC this method and use getter chains to extract the property values you need.
If you are looking for something lower in the stack you can try seeting a MIDC on System.ServiceModel.OperationContext class
https://msdn.microsoft.com/en-us/library/system.servicemodel.operationcontext(v=vs.110).aspx
You can create MIDC with something like following
```
Class : System.ServiceModel.OperationContext
Method : get_Current (this is just the internal getter method for the Current property of OperationContext class)
```
Now get_Current will return the current OperationContrext so you can apply a getter chain on this object to extract what you need.
Thanks,
Raunak