I am afraid no digital sound is transfered via the link system...
Had the same issue with movie sounds.
Ralf
My Beo: Beosound 3000, Beolab 4000, Beo 4 DVD, Beolab 5000/Beomaster 5000, Beovox S45.2 with Stands, Beosystem 7000 black with Beolink 7000, Beolink 1000, F1000 (3 cubes), Beovox 5000, Beovox 3000, Attyca 1.