Palm earlier this month released a Windows Mobile 6 update for AT&T customers with Treo 750 smartphones. But it turns out that Treo 750 users are unable to utilize Windows Live. Instead, they're restricted to using AT&T's Xpress Mail and instant messaging, as one very unhappy AT&T customer pointed out.I initially wrote a story on Dec. 5, alerting AT&T customers that there's now a Windows Mobile 6 update available to them, which offers users additional capabilities that were lacking in the previous version.

As I pointed out in my story, one of the major enhancements is faster access to large attachments, streaming video, and other bandwidth-hungry content and files. The update also provides the ability to sync the Treo 750 to a Windows Vista PC via Microsoft's Windows Mobile Device Center and direct "push" technology that delivers e-mails to the phone straight from Microsoft Exchange Servers.

I recently got an e-mail from an unhappy AT&T customer who spent over an hour on the phone with Palm's technical support, and here's his recollection of what he found out:

There is no Windows Live in the AT&T version. AT&T stripped it out. They want you to use Xpress Mail and their instant messaging instead of Windows Live. Palm support installed Windows Mobile 6 on an unlocked Treo 750 and it did have Windows Live, so it was AT&T's decision. I pointed out to Palm that the manual that you download with the Windows Mobile 6 upgrade has Windows Live in it. That really made me mad.

I really feel cheated by upgrading to Windows Mobile 6 (there is no downgrade to version 5) and losing Pocket MSN (which was now replaced by Windows Live and not included in the AT&T version). This is a bad image for those of us who have been waiting for almost a year for the upgrade.

I called Palm to get their side of the story and a spokeswoman confirmed that it's true, AT&T decided to include its own services rather than go through Windows Live. The spokeswoman said that, ultimately, the available features in a phone are decided by the carrier. Many of us are already aware that carriers have a tight grip on phone features. But for a carrier that calls itself the most "open" in the United States, AT&T really has a way of locking in its customers.

Palm does offer an unlocked version of the Treo 750 that has Windows Live. Unfortunately, that doesn't benefit those of you who already have purchased the smartphone from AT&T.