Airplay sound output with Infuse


I use to make my atv2 work with an airport express to send sound on an external source instead of HDMI or Optical.
(In Settings/Airplay => output on Airport Express)
It does work very well with films, trailer, music in iTunes app, but doesn’t work with Infuse.
Is there an issue to make that feature work with Infuse ?? Because I can’t here another source than the HDMI one…