IPhone 4S: Ringtone (no vibrate) for calls; but vibrate (no sound) for texts?

I just got a new iPhone 4S for my birthday. I want to set it so that, every time someone calls me, it plays a ringtone but doesn't vibrate. I also want to set it so that, every time I get a text, it just vibrates and doesn't play any sounds. How can I do this? Nothing I've tried works.

Try tweaking the "Sounds" settings in the "Settings" app, as well as the "Messages" and "Phone" settings in the "Settings" app. You might find out!