BB Curve :: Standby Doesn't Work Anymore Since Updating?

I updated my Blackberry 8900 Curve over the weekend to v5.0.0.1036(Platform 5.2.0.104) Provider is [URL] This updated was offered when connecting my device to BlackBerry Desktop Application.

After this update successfully took place I discovered the problem that the upper top right button (usually used to mute) does not send my device to standby anymore when being pressed longer than 3 seconds. This function worked perfectly prior to this update. Unfortunately I did not know on what version I was before, but as I`m doing updates on a more of less regular base I assume it was the prior available one.

Together with this problem I discovered something that is also working different than before. When I press the keyboard lock button (upper top left button) the lock now gets activated directly and the screen turns black. Before this update took place the owner details were showing up when pressing this button and the screen turns dark after the defined time to go off. The owner details are added correctly and show up when going to properties-owner.

I did a secure delete (security options - security delete) of the device and started from scratch twice already, but the problem remains the same.

Is there any way to get at least the standby working again. I´m using an case-mate holster with build in battery allow me to recharge my BB when no power plug is avail. Unfortunately this one does not have a magnet that send the device to standby automatically when plugged into the holster, so this manual standby option is important for me to extend battery life.