Have you tried scenting the room with the f/t before you actually give it to entice a feeding response? I was reading the other day on someone else's post about how they use a hairdryer to warm up the f/t and that they point the hairdryer air toward the cage. The drying and warming of the f/t should be wafting very well into your snake's nose :p.
Also, how long do your attempts to feed usually last and how often do you attempt?
Have you tried messing the with temps? It could be possible that your snake isn't at the right temps, try raising your temps like Lady stated above.
Hope this helps.