Airport extreme after linsys router not finding my synology disc/sonos system

My airport extreme is configured as bridge after a linksys (wifi) router. Using the airport I don't see the shared folders on my synology(DSM 4.2) in finder, except by connecting through the IP. This also means timemachine doesn't work using the airport network. Synology has fixed ip in network. Using the linksys wifi network or networkcable everything works fine. Same problem for my sonos system that isn't discovered through the airport network except after switching to the linksys network first.