Ah ok, looking at that, Dragon Age is pulling all the data it needs for the material from different colour channels in the texture ("R/G/B/A"), specular being the alpha-channel. Doing what it is, there's going to be an issue with your alpha - either its not there or there's some other problem with it, so check you do indeed have one - it should show up in whatever photoediting app you're using in the "Channels" panel.
I tested the process with CorelDraw and using the images from that link you posted managed to produce what looks like a correct image by splitting the channels into separate images using "Image >> Split Channels to >> RGB". I then dropped an actual normal map into the Red channel image, the Diffuse into the Green channel image and Alpha Mask into the Blue channel image. I then have to recombine the RGB channels back into a single image with "Image >> Combine Channels..." and then 'load' in the actual Alpha Channel image as a separate object over the top (from the "Mask" menu). Seems to work ok doing that.