uri65,
I think i'm having the same trouble. I want my alarm to ring quietly- it doesn't take much to wake me up- and nothing worse than a blaring sound to jolt me out of bed. However, I want my phone calls to ring loudly. If I set the volume low at night for my alarm to ring quietly, I forget to set it back up in the morning and then I can't hear my phone ring with a call or text message.
I found a free app called Nightstand Central. I set the alarm and volume the way I want but it doesn't change my phone volume setting so I can leave that up (I don't have an issue with getting phone calls/texts at night). Yes, I'd like that functionality directly in my clock --> alarm settings in my phone but this is an ok work around and was free.