Ulrica,
What your description of the "mitella" is what we call a "sling". Yep, that's right. If I break my arm, I will have to put it in a sling for a while as it heals. In english (or at least american) we call any device made of flexible material intended to support something a sling.
My wife has a large fabric thingy that she carries our babies in - it is called a sling.
When workmen lift a large piece of material with something wrapped around it (like a cable, nylon rope, etc.) it is called a sling.
As for survival use of the sling: I am certain it would only be useful as a food gathering device with much practice beforehand.
You could use it as a snare. Or maybe you could catch a deer and use the sling as reins and ride the deer out of the woods.
I suppose the possibilities are endless, I just can't think of anything else right now.
jeff <><