Unable to remove Message Type, (outer node) from REST receiver adapter

Hi

I have a ECC - PI - Webservices synchronous interface. I am using REST receiver webservice. I am using Java Mapping to convert xml to JSON and I am not using the conversion option in the REST adapter. The reason I am using Java Mapping is because I have two force array in a particular table. The materialMaster is a table. It comes as object in the payload if there is only one set of value and as an array if there are multiple sets of values. So I am using Java mapping to force array.

In the REST Receiver communication channel, under the Data Format tab, I have clicked the check box next to "Strip Operation from Mesage (Outer Element)" but still I am getting the outer node, MT_MaterialMaster in the target payload.

I have attached a screenshot too.

Why is it that the MessageType is not taken off from the payload?

Regards

Harish Babu