Maps from contours is possible BUT it take a lot of patiance to get it right. I ought to know as its how I have done ALL the Falklands maps.
BMP-XYZ is good (its mine!) BUT when Visitor came out I found that I could save the files as tga's and use the tga-ase converter and take them straight into Visitor that way.
Either way the hard part is actaully scanning the map into the computer, then tracing the contours, then filling each contour level, then smoothing the whole thing out (this last part is the problem as you can lose defintation if you do the smoothing to the whole map. I found I had to do the maps in sectinos to allow for the different elevation changes.
Not sure if the BMP-ZYX is hosted anywhere else so I will check to see if its still on my ftp, and get the link here if you need it.