One can always try an appeal to BMW NA (in this case)...but if the answer is no and you don't want to pay for a new seat or "skins" with the wiring sewn into it...it can be repaired DIY style. Again, there are a couple of DIYs on e38.org of owners removing the seat & peeling back the leather to
repair (not replace) the broken wire.
EDIT: Here's another DIY found on Bimmerforums e38 board:
http://forums.bimmerforums.com/forum....php?t=1165042
(you can see how the broken wire was found, and resoldered to fix the issue)

BTW...this is issue and the front passenger seat occupancy mat sensor is the reason why I NEVER kneel on the seat and will IMMEDIATELY stop any passenger from placing their knee in the front seats for any reason.
My reasoning is that placing a knee on these seats puts a high concentration of weight on the heating sensor wires and occupancy sensor wires which causes them to fail/break. I may be over-cautious but it does seem plausible in my small mind.