There is never an easy way to do something like this. I don't know how you have your textures setup, so I can't help.
If you send me the files, I can help. After working with ST on detailing his choppers, I have quite a few things that might work, but it's really mostly trial and error. I personally would try to make the side and top down views of that area line up pretty nicely, then rotate around the model until you can get the rounded part as a flat plane, so that when you are looking at the polygon, you only see a flat polygon, then texture that polygon, then check it, then redo.. over and over.
There must be an easier way, but I'm not a modeler by trade, so I would have no idea how a "real" modeler would do it.
Ebud