See what the manual says about sounds
http://manuals.info.apple.com/enUS/iPhone_UserGuide.pdf , page 159
Sounds and the Ring/Silent Switch
Switch between ring and silent mode: Flip the Ring/Silent switch on the side of iPhone.
When set to silent, iPhone doesn’t play any ring, alert, or effects sounds. It does, however, play alarms set using Clock.
Note: In some countries or regions, the sound effects for Camera and Voice Memos are played even if the Ring/Silent switch is set to silent.
Set whether iPhone vibrates when you get a call: Choose Sounds. To set whether iPhone vibrates in silent mode, turn Vibrate under Silent on or off. To set whether iPhone vibrates in ring mode, turn Vibrate under Ring on or off.
Adjust the ringer and alerts volume: Choose Sounds and drag the slider. Or, if no song or video is playing and you aren’t on a call, use the volume buttons on the side of iPhone.
Set the ringtone: Choose Sounds > Ringtone.
Set alert and effects sounds: Choose Sounds and turn items on or off under Ring . When the Ring/Silent switch is set to ring, iPhone plays sounds for alerts and effects that are turned on.
You can set iPhone to play a sound whenever you:
Get a call
Get a text message
Get a voicemail message
Get an email message
Send an email message...
So,
1) not possible to have only one sound for SMS out/in
2) use the ring/silent switch
3) Alarms set by your clock will have sound, even in silent mode (ring/silent switch switch active)
Message was edited by: Ingo2711