I live in BC Canada, where it is illeagle to even so much as touch your cell phone while you are driving. If you are caught, it's a $167 ticket, not to mention that people using cell phones kill more people a year here than drunk drivers.
As the rest of you, I have also encountered this problem of not being able to voice dial from my bluetooth. You would think that in March 2012, this would have ceased to be an issue, but apparently not.
I called my carrier, Rogers, who said they did not support the device they sold me, only the network. They went on to say that I may be able to download an app to make it work, but they wouldn't tell me which one, because it may break my phone!!! Really??? So Rogers told me to call Samsung.
I called Samsung tech support and Louis told me that it was a compatability issue between my phone and my bluetooth. I then went on to ask him which Samsung blutooth would work with my Samsung phone. He told me he didn't know, because he was the phone support guy. I asked him to put me in touch with the blutooth support gut, but he advised me that they have no such department. Go figure!
I finally found this on the Samsung website today when I queried my phone:
Hands-Free Profile (HFP):
The HFP Bluetooth profile allows a connection from the phone to a wireless Bluetooth-enabled car kit. Incoming calls ring to the hands-free headset or device. Calls can be received by pressing a button on the Bluetooth headset or device. As for dialing, four functions are supported: recent call dial, voice dial*, speed dial, and number dial. You can increase or decrease the volume by using the volume key on the side of the phone.
*Note: While the standard HFP Profile does support voice cialing, the SGH-i616 handset features a voice recorder, but does not include any configurable options for voice dialing with or without a Bluetooth headset. There may be 3rd party applications which will provide voice dial capabilities, however there are no options fur voice dial via the use of a Bluetooth headset.
In short..... you can't voice dial a Samsung Galaxy S ii LTE with a bluetooth headset period. Why does Samsung know this, and not find a fix for it, and then continually lie to their cusrtomers???
I'm done with Samsung..... no more TV's, no more cell phones, no more monitors, and what ever else they might manufacture. Maybe my old Blackberry wasn't such a bad thing.
March 24, 2012. I just called Samsung again, and spoke to an honest Tech Support person. He advised me that none of Samsung's phones on the Android platform will voice dial from a bluetooth. He could not offer any advise as to whether or not this issue will be rectified. He told me to try Vlingo. I've tried Vlingo and a handful of other apps, all without success.
So....I'm thinking of causing a ruckuss with my provider, and if all goes well, I think an iPhone is in my future.
March 28, 2012. Ok, I have to admit, I can be like a dog with a bone at times, but I think it paid off here. Today I downloaded an app called Choice Dialer +. At first it didn't work to voice dial, but I took the battery out of my phone and waited 5-19 minutes and put it back.... voila! It now voice dials with my bluetooth! It doesn't have super great voice recognition, but it does work.

It even works when the screen is locked.