It has been a while since I worked with this and it may have been updated. This might not be your issue but I my camel-server.xml looks like this, note that the converters and aliases tags are not necessary, but if you find yourself needing an xstream alias or convert, that is where you would configure them. I would check your server log file too.
<dataFormats>
<xstream id="xstream-json" driver="json">
<converters>
</converters>
<aliases>
</aliases>
</xstream>
</dataFormats>
<route>
<from uri="cxfrs://bean://rsServer"/>
<policy ref="droolsPolicy">
<unmarshal ref="xstream-json" />
<to uri="drools:node1/ksession1" />
<marshal ref="xstream-json" />
</policy>
</route>