While writing this I am watching ARTE HD, the best of 2011 for classical music, I can tell you that in some pieces they use the LFE
ARTE only broadcasts dolby surround signals in 2.0, there's absolutely no transmission of a .1 channel.
The signal that you obviously hear from your subwoofer is being created by some kind of bass management of your receiver.
You shouldn't think about using the LFE channel for a music soundtrack as it's not made for that purpose, most soundtracks are in fact only 4.0
best regards
Florian