Achievements should unlock, yes. Can you tell me how you set up the achievement that doesn't work? (or go and edit it, and then take a screenshot).
Achievements 3 Beta 2 doesn't have tight integration into BuddyPress yet; it doesn't add itself to the BuddyPress navigation bars, and so on. If you look at the "howdy" menu on the WP toolbar when you're logged in, it does add a "achievements" item which takes you to a list of your unlocked achievements.
Really I'm waiting for BuddyPress 1.7 to be released (end of January?) before integrating Achievements 3 tightly into BuddyPress again.
You'll probably want to create a custom menu, and in it, add a custom link pointing to http://example.com/achievements/ (where example.com is the URL of your site). That's the new home for the "list of all achievements" page.