I don't want to harp on about the dripping icicle but if you think about sound in the wampa cave. The sound is the main problem.

If you play the sound of a dripping icicle off (and visually represented) against luke trying to pull his sabre out of the ice and it's really quiet in the cave.

As far as the musical score goes it might need playing with also to get the right effect.

without going too overboard elements of retro synth for otherworldly feel here could be what is actually needed rather than lukes theme and Willams score mostly removed along with the wampa groaning.

http://www.youtube.com/watch?v=ho097qauXN4

http://www.youtube.com/watch?v=hh0laxfU5zc

http://www.youtube.com/watch?v=CvGmQcUvaxc

http://www.youtube.com/watch?v=ry6oY0oGAZ0

http://www.youtube.com/watch?v=WXM1IGiEhyk

here are some arp odyssey sounds. and I only mean minimal use of something like this in a sfx capacity

http://www.youtube.com/watch?v=G4SbDBGc2BY

at 3.46

ttp://www.youtube.com/watch?v=xHRgCKgbiVk

0.03 /2.42 / 5.07

Horror fx

http://www.youtube.com/watch?v=bh6L44rVaas

01.35 on this one is great

Although giving many examples I mean very minimal use of any sound it has to be quiet

Luke does not know if the wampa is there or not because we can not hear him at all moaning or groaning constantly like he's committing suicide. we also don't see him until he springs out from wherever he comes from.

Luke trying to be quiet will be greatly enhanced, and all that can be played with in this sequence is fear of the unknown that is the angle.

That was what I was trying to get at here, sorry but this train of thought has taken it's time to come to fruition and explain it more properly.

a lot easier said than done though probably