Which provider are you working with? It sounds like they are using IP authentication, which means that all you need is to point your PJ-SIP settings at their server and away you go.
Connecting without Peer and User details is actually pretty simple these days, thanks to PJ-SIP settings. Peer and User settings are a Chan-SIP thing, so if you go with PJ-SIP, you should be able to connect pretty simply. See this post: PJSIP trunk between servers for more information.