How to retrieve return value in out interceptor?

[New Groovy]

Hi,

I want to filter some return values in an out interceptor, but am
struggling to figure out how to retrieve it.

I have tried this:

        MessageContentsList outObjects =
MessageContentsList.getContentsList(message);
        Exchange exchange = message.getExchange();
        OperationInfo op = exchange.getBindingOperationInfo() == null
                ? null
                : exchange.getBindingOperationInfo().getOperationInfo();

and see a lot of info...but can't figure out how to retrieve the _return
value I see in the xxx.jaxws_asm

Any pointers?