Open Manage problem if Server Name has an underline

I installed a server awhile back, and Open Manage wouldn't work. Tomcat problem. I wasn't sure why so I recreated the setup in a sandbox. Tomcat itself can handle a servername with an underscore, with SSL. But omconfig cannot create a self signed cert if the servername has an underscore, keytool with java can. Something is up with omconfig or this is just not supported with Open Manage. I had to create my own self signed, import with omconfig, but can only resolve the webpage if I do localhost instead of abc_server.