UDO supports — did you think anything else — dashs like in this sentence.
Dashes are supported by LaTeX, RTF, and WinHelp. The other formats replace those two or three minus characters by one.
If you want to create a long dash, use ---. A medium dash is created with --. But if you have to output three minus characters, in a row, you have to use (---) in your source text. Use (--) accordingly in the source text, to get two minus characters.