OK. First, I had Rank Resets before, so I don't lose my data (2 gold medals to onyx for seriously). When I have rank reset before, I go back to the dashboard, then I start Gears 3 again and selected the memory unit to load my data and Rank Reset is gone.
But Saturday was a different thing. I have the beta dashboard now, I played "Body and Brain Connection" before Gears, and when I started Body and Brain, disconnected me from Xbox Live. I finished playing and went to the dashboard, and I see my friends and everything from the dashboard, so I supposed that I was connected to Xbox Live. Then I started Gears 3, selected HDD and the message from unlocking weapons skins appeared! The first time I was scared, but not now. Well, after the unlocking messages, the party was set to local, and I went to the dashboard. I log out and on again, I verify that I was connected to Xbox live, and started Gears , selected HDD again, wondering if I'll see lvl 1 white again, but everything was all right (My veteran lvl, medals, ribbons, etc).
It's my first time that a Rank Reset wasn't a Rank Reset, and I didn't need to do the backup thing