When a terrain is submitted to htc, it must include all the terrain source files including all .til, .bmp, .ac and .htx files, to name a few of the more exotic files. Your .res output file by itself doesn't come close to qualifying. By the way, all these files and the work they represent become the property of htc when you submit them.
If the terrain must pass review by the terrain team, the requirements are the same except that you may withhold the .ac and .til files (your custom object sources) until you submit it to htc.
Since anyone along the review process can reject the terrain, due to quality or game play issues, it's best to contact the appropriate reviewers before you put too much effort into it, especially if it's not historically based.
