I too am having issues getting Soundbridge to talk to Firefly via Livebox. I can get radio working on the Soundbridge, and can see the radio working via VisualMR, but no sign of Itunes or Firefly in the SB or VisualMR.
In My Network Places I can see the soundbridge, but clicking on it results on a “device offline” message.
I can run Windows Media Player via the Soundbridge, so everything appears to be working as it should. I just cannot connect to Firefly 1586.
I should add here that the identical setup worked fine using a DLink router.