Dell Inspiron 9400 - Anyone had any luck getting Sigmatel chip to output SPDIF signal to receiver?

Hi all, Recently got my hands on a Marantz 5.1 receiver with SPDIF in. Notebook I have (which plays the part of media PC when I'm at home - XBMC running over WiFi using NFS + MySQL) is a Dell Inspiron 9400. Has a Sigmatel audio chipset with a breakout cable that provides SVHS and Composite video alongside SPDIF audio output. The latter I can't figure out how to activate under Ubuntu (had 11.04, upgraded to 11.10). Tried setting pulseaudio device profile to IEC958 out and didn't make any difference. There were some IEC958 tickboxes in gnome-alsamixer too that didn't seem to do much. Anyone ever used the digital output of a Dell notebook with a sigmatel codec in Linux? Any modprobe argument magic needed? Anthony