Volume Buttons not functioning at all after repairing screen?

I realised that i tore it when i was prying the metal plate apart. But now the device has the so called "White screen of death", which requires me to use the lock button to get out of (which wont work). Is there a way to get out of this mode without using the sleep/power button? I know the device functions perfectly, because when i hold the home button, voice command comes up, and i tell it to play a song, and it does. Any suggestions?

The cable needs to be replaced. It's soldered onto the logic board. It is possible to do it using a soldering iron and a very fine tip (and a steady hand!). We will have a guide up eventually to detail the process. In the meantime, to get it out of the white screen of death, I would just wait for the battery to deplete and then plug it into an AC power source. That should take care of it I think.