redirecting guest serial to file on the host

[daggs]

Greetings,

I have a vm to which I can access using virsh console vm1/
I'd like in addition to be able to dump the serial of the vm in to a file on the host.
I've found this https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/6/html/virtualization_administration_guide/sub-section-libvirt-dom-xml-devices-host-interface but it seems that the first second example which might be suited to what I need doesn't work as I get an empty file:
here are my serial config for the vm:
    <serial type='pty'>
      <source path='/dev/pts/2'/>
      <target type='isa-serial' port='0'>
        <model name='isa-serial'/>
      </target>
      <alias name='serial0'/>
    </serial>
    <serial type='file'>
      <source path='/var/log/router-serial.log'/>
      <target type='isa-serial' port='0'>
        <model name='isa-serial'/>
      </target>
      <alias name='serial1'/>
    </serial>
    <console type='pty' tty='/dev/pts/2'>
      <source path='/dev/pts/2'/>
      <target type='serial' port='0'/>
      <alias name='serial0'/>
    </console>

what might be wrong in the above?

Dagg.