I made a set of special palettes to convert units from one game to another... just convert the RA file to PCX, load the special RA palette in it (keeping the palette order), then load the TS palette in it (matching nearest color), save the file and convert it to TS SHP.
The palettes pack can be downloaded on the bottom of the mods page of my website:
The palettes are raw C&C palettes and Paint Shop Pro palettes. I used Paint Shop Pro 3 to make them (see http://www.jasc.com)
Make sure you read the readme file in the palettes pack to see which are the raw and which are the PSP palettes.