In its current form, Settings is not really up to the task you want to use it for.
The problem you'll run into, if you haven't already, is that you'll want to verify the user's information somehow. Maybe they entered the server name wrong, or made a mistake in their password. What then? Keep sending the user back to Settings to try again, then switching back to your app to find out if they got it right this time? That's going to be a lousy user experience, and the best way to fix it is to give the user the option of changing the settings in your app so you can verify the information immediately.
Only once you've done that, poof, you don't need to use Settings for this anymore. You can just send users to that account-edit view immediately when your app launches for the first time. Your users get a better experience, and you're saved the trouble of trying to find a good way to get users to find your app's configuration in the Settings app.
Apple does this already-- just look at mobile mail.
