The phone does not lock like it used to prior to the update. You can put it in "sleep" like mode by holding the A key down. You will notice a lock on that key.
From the main screen, press Blackberry.
Scroll to Options, press Trackpad.
Scroll to Password, press Trackpad.
Options shown below:
Adjust as needed, press Blackberry. Scroll to Save, press Trackpad.
Hope this Helps!
Easiest thing to do is "update" your software by downloading an earlier version that will restore the option using your softkey to autolock the 8530
Make sure your phone is connected to your PC with the USB cable and click the update button.
Use version 188.8.131.527 to get this function restored.
Takes about 20-30 minutes to download and update-worked like a charm!