Spring Integration: Content based router with default output channel?

Turns out that all I had to to to make this work was to set the router's ignore-channel-name-resolution-failures attribute to false:

<int:router input-channel="channel_in" default-output-channel="channel_default" 
  expression="payload.name" ignore-channel-name-resolution-failures="true">
    <int:mapping value="foo" channel="channel_one" />
    <int:mapping value="bar" channel="channel_two" />

I thought I had tried that before, but I seems I didn't.