Just thinking about what it would require to get it to work gives me a headache. I haven't done a DX7 to DX8 conversion in ages, and I am proud of it - its a horrible process full of crashes, bugs and problem solving.
First thing you would have to do is convert your tiles from one huge graphic because you work in textures. This is a good first step anyways, though. Its easier having one huge graphic (if your computer can handle it), but you have to load that whole thing into one surface, which means it will be stuck there... as a whole. If you do it individually, you can automatically unload textures when they go unused for too long, and load them up when you need them (and they're unloaded). Huge bonus to the RAM usage.
Secondly, you have to convert them to powers of two - if your texture isn't a power of two (2^X), then it will end up stretched and distorted, and just nothing that you wanted.
Lets see... then you have to start with the drawing. Not sure where to tell you to start on that, but you will want to know how Tu and Tv values work. Basically, you will probably want to do a Triangle Strip, which means you define 4 verticies:
Code:
0-------1
/
/
/
2-------3
This is what will make up your graphic. As you can see, its just two triangles. The values you will have to worry about are the X, Y, Tu, and Tv. X and Y are self-explanitory. Point 0 is (X,Y) while point 3 is (X + Width, Y + Height). Tu and Tv are the texture co-ordinates, in percentages. So if you have a 512x512 texture, and you want the first 32x32 tile, you would have:
Point 0: (0 / 512, 0 / 512)
Point 3: (32 / 512, 0 / 512)
Tu = texture X, Tv = texture Y.
There a starter for ya.