Issue with Camel Velocity Component Output where headers are cleaned out after processing

Issue

• Facing an issue in using Camel Velocity component where all the existing headers are cleaned out once exchange is processed by Velocity component.
• Sequence Workflow is below
  • Accept a file over file endpoint (E:\In) and send to a JMS queue for further processing..
  • From JMS queue, call xslt component (available in E:\XSLT) to do transformation and then hand over to velocity component (available in E:\XSLT) to create a wrapper response.
  • Finally write the response from velocity to a file (E:Out).

<camelContext id="xslt-velocity-test-adaptor" xmlns="http://camel.apache.org/schema/spring">
        <route id="File_JMS" startupOrder="1" autoStartup="true" streamCache="true">
            <from uri="file:///E:/In"/>
            <to uri="activemqLocal:queue:TEST.IN"/>
        </route>

        <route id="JMS_File" startupOrder="2" autoStartup="true" streamCache="true">
            <from uri="activemqLocal:queue:TEST.IN"/>
            <convertBodyTo type="java.lang.String" charset="UTF-8"/>
            <to uri="activemqLocal:queue:TEST.TEMP"/>
            <to uri="direct:xsltProcessor"/>
            <to uri="direct:fileOut"/>
        </route>

        <route id="xslt_processor" startupOrder="3" autoStartup="true" streamCache="true">
            <from uri="direct:xsltProcessor"/>
            <doTry>
                <to uri="activemqLocal:queue:TEST.TEMP"/>               
                <to uri="xslt:file:///E:/XSLT/test.xsl?allowStAX=false"/>
                <to uri="activemqLocal:queue:TEST.TEMP"/>
                <to uri="velocity:file:///E:/XSLT/test.vm"/>                    
                <doCatch>
                    <exception>org.apache.camel.RuntimeTransformException</exception>
                    <handled>
                        <constant>true</constant>
                    </handled>
                    <setHeader headerName="Exception">
                        <simple>XSLT Transformation failed with ${exception.message}</simple>
                    </setHeader>
                    <log message="Error in message processing. Exception message is: ${exception.message}" loggingLevel="ERROR" logName="com.test" />
                    <to uri="activemqLocal:queue:TEST.ERROR"/>
                </doCatch>
            </doTry>
        </route>

        <route id="file_out" startupOrder="4" autoStartup="true" streamCache="true">
            <from uri="direct:fileOut"/>
            <to uri="activemqLocal:queue:TEST.TEMP"/>
            <recipientList>
                <simple>file:///${in.header.CamelFileParent}/?fileName=../Out/${in.header.CamelFileNameOnly}</simple>
            </recipientList>
        </route>
    </camelContext>