Default I want my HTC Desire X downgraded to Android 4.0 ICS. Please help

I recently got my HTC Desire X upgraded by the HTC care people. They upgraded my HTC Android 4.0 ICS to Android 4.1 JB. I'm quite irritated with the new Android, as my favourable options are missing from my phone, mainly being MASS STORAGE. I hate it when my phone drives and removable drives open just like some folder, when I connect my phone to pc. I used to access them like separate drives with MASS STORAGE option when my phone had Android 4.0 ICS. Please help me. I seriously want to go back to Android 4.0 ICS. Can I downgrade? When I asked HTC Care guys, they said that they dont have the facility to downgrade. Please suggest some way to get downgrading facility.