Hi Miguel, I don't know whether you are still seeking an answer to your problem? From the FAQ's U8800 Manual:
2.8.2 How many wrong unlock patterns will lock the phone
If you lose the screen lock password, the phone will be permanently locked and unusable. You can download U8150 version software from the Huawei Website,
(Support - Huawei Device Co., Ltd..
), to upgrade your phone.
Please refer to 2.1 Force upgrade.
2.1 Forced Upgrade
The forced upgrade method is as follows:
Note: After the forced upgrade, all user data (contacts, text messages, and multimedia messages) will be lost.
1. Go to Support - Huawei Device Co., Ltd..
and search for the latest U8150 version, download it to the local drive, and uncompress it to extract the upgrade file.
2. In the SD card root directory, create a new folder named dload. Take the extracted upgrade file, UPDATE.APP, and copy it to the dload folder.
3. Insert the SD card into the mobile phone.
4. When the mobile phone is powered off, press the Volume +, Volume -, and Power keys at the same time to initiate the forced upgrade.
5. After the upgrade is complete, restart the phone, and continue to use as before.
Obviously, your teenager went into > Settings > Location & Security > Set up screen lock > Pattern > may have entered a PIN/Password or not, but the only recourse you will have is to follow the Forced Upgrade procedure and it will bring your phone back to as new state.
I've done this with a U8150 Ideos I purchased which had a screen lock set by the previous owner - it works - no hassles. Cheers Neil.
ps. I'm a little concerned that the Manual tells us to Download the Latest U8150 Version (Froyo 2.2) it should work.