WSO2 MongoDB GridFS - mongodb

Question

I am new to WSO2. I'm using wso2ei-6.5.0. I'm trying to add MongoDB GridFS interaction to a data service I already have working with MongoDB. I'm not finding any information in the WSO2 documentation. Does anyone have any samples that can help me?
Working MongoDB data service code. This will only insert documents into normal Mongo collections, not the GridFS collection where binary data gets stored in chunks.
<data name="MongoDB" serviceGroup="" serviceNamespace="">
<description/>
<config id="MongoAudit">
<property name="mongoDB_servers">localhost</property>
<property name="mongoDB_database">audit</property>
<property name="mongoDB_write_concern">FSYNC_SAFE</property>
<property name="mongoDB_read_preference">PRIMARY</property>
<property name="mongoDB_maxWaitTime">60000</property>
</config>
<query id="mongoInsertAudit" useConfig="MongoAudit">
<expression>mycollection.insert("{ correlation_id: #, flowname: #, payload: #}")</expression>
<param name="correlation_id" sqlType="STRING"/>
<param name="flowname" sqlType="STRING"/>
<param name="payload" sqlType="STRING"/>
<result element="UpdatedRowCount" rowName="Row" useColumnNumbers="true" outputType="XML">
<element column="1" name="Value" exportType="SCALAR" xsdType="xs:integer"/>
</result>
</query>
<operation name="mongoInsertAuditOp">
<call-query href="mongoInsertAudit">
<with-param name="correlation_id" query-param="correlation_id"/>
<with-param name="flowname" query-param="flowname"/>
<with-param name="payload" query-param="payload"/>
</call-query>
</operation>