First, I would recommend going back to a standard hyphen rather than an em dash. Em dash is a non-standard character. Very few users would even realize the difference between that and a hyphen and even if they did, they wouldn't know how to type it.
Disclaimer aside, if your links are being generated properly when you browse the site, your search engine should be picking them up. Did you just run the indexer or did you do a "Clean re-index"? If it is still not getting the correct URLs after a clean re-index, I would double (or triple) check your configs and then contact Forward Search support.