Xperia U ST25i (Android 2.3.7 - Gingerbread) - Where is Developer Options?

There is some way to active developer options in 2.3.7? When I bought my Xperia U, they came with developer options and 2.3.7 android. How it works? I tried press 7 times on build number and those thing, but nothing worked, someone can help me, PLEASE? I don't want to use ICS, JB or some different android. Thank you, guys!