Read https://discussions.apple.com/thread/3378150?start=15&tstart=0 if you didn't know this one. I didn't.
I have an iPhone 5, friend of mine has an iPhone 4S - when we send Text messages it does not send via iMessage (Blue Clouds on Screen), it sends via Text.
All my other friends w/ iPhones I do not have a problem with only this one.
We have checked the settings, specifically how to send 1st iMessage and on both iPhones are set to the Cell Phone number, not email addresses.
I have gone through the Manual and we have re-checked everything - really cannot figure this one out.
Any help is appreciated.

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