Hi there Joe,
Yes it sounds like maybe the specular is not right. A first question to ask: Does your texture show 'any' reflectivity at all in FSX? If there is some showing, then at least you know you are on the right track.
I'll review some of my notes on this and post back with what I find. In the mean time, I've done some writing on this subject in a tutorial I wrote for FS2004. The basic concepts should still apply with FSX, at least they're worth a try.
http://www.simmerspaintshop.com/foru...ng-fs2004.html