I have a i717 on straight talk. Everything works great, mms and internet with speeds around 6Mb down / 2 Mb up. I'll get a screen shot with my latest settings for you. Very simple, couldn't be happier really. Just be careful about going over 200mb per day and 2gb per month.
You do not needed to unlock it. Mine is not unlocked, works great.
Sent from my SAMSUNG-SGH-I717 using xda app-developers app
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