hmm now with your not being able to see from inside of the model, i know that if you have back face culling turned on it will give you that problem. You can turn it on and of here..

Display
Custom Polygon Display - click option box
scroll down and turn backface culling off.

hope this fixes your problem. If not, it maybe something to do with the way you have applied your uv mapping. Try giving it automatic mapping then re apply the uvmapping again. That works for me.