Took a look for you.
When imported to modeling program, it appears you have created a lot of planes on which the uv's are fine, however each plane is individual and has a separate material ID.
Suggest you attach all the planes together and apply the material to it before exporting, .x stores the uv and material ID's in the file, so this should fix it for you.
Normally I would expect this to work, even as is, if applying the texture in FPSC, but all those material ID's might be confusing the engine.
Also you have no alpha channel in your texture for transparency. Since the editor shows a preview of the texture it may be that your seeing no detail and it looks like a block of colour and with no transparency your only going to get square textured planes anyhow.
Last but not least, this is a pro made texture for use with alpha transparency, whoever created it really knows what they are doing, hope its your own, particularly since I've downloaded it

Even many pro's don't bother with feathering for transparency, but when they do you know for sure they work in the games industry.
I don't trip over...I do random gravity checks.