Default [Q] Sensation XL cant boot after changed button config

Hi , i have a htc sensation xl which is in good nic.
The power button managed to die and i decided for the mean time to change the power button config to the volume button.
The software asked me to reboot the phone and i disconnected the battery and tried to turn it on by plugging it into charge or into the pc while holding the volume down key..

Now the issue is im sure is that since it is set to volume it doesn't want to boot.

Is there anyway around this?

or is it stuck until the power button is fixed?

Also to fix it do i need to replace the whole upper flex which includes the power button volume sensor etc