the difference on pfsense 2 between OpenVPN RoadWarrior and Site-to-Site is just the options in the GUI.
For a site-to-site connection you do not use Username/password so this option isn't available when selecting sito-to-site.
But the OpenVPN server is working the same - no matter if you selected site-to-site or RoadWarrior.
If you already found your answer - that's nice to hear and you can forget about my post
