The Object you get is a ByteBuffer instance, so even though the implementation is private, you can still access the data in there by assigning it to variable of type org.apache.mina.common.ByteBuffer.
Mediation Router (Camel) should support converting this into a byte, String, InputStream and ObjectInput, so I'm not sure what the problem with the getIn.getBody() as data\[\] is. Could you enable DEBUG logging in the ESB for the org.apache.camel logger and check if the MinaConverter is actually loaded? If it is, is there any additional log output when conversion should occur?
After logging for camel is enabled on DEBUG I get lot of messages like:
Could not find class 'org/apache/camel/component/mina/MinaComponent$1$1.class'
Could not find class 'org/apache/camel/component/mina/MinaComponent$1$2.class'
Could not find class 'org/apache/camel/component/mina/MinaComponent$1.class'
Could not find class 'org/apache/camel/component/mina/MinaComponent.class'
Could not find class 'org/apache/camel/component/mina/MinaConsumer$1.class'
Could not find class 'org/apache/camel/component/mina/MinaConsumer$ReceiveHandler.class'
Could not find class 'org/apache/camel/component/mina/MinaConsumer.class'
Could not find class 'org/apache/camel/component/mina/MinaConverter.class'
After lot of messages like that there's another one:
Could not examine class 'org/apache/activemq/camel/converter/ActiveMQMessageConverter$1.class' due to a java.lang.NoClassDefFoundError with message: org/apache/camel/Processor