Responding to touchesBegan in UIPickerView instead of UIView

I have a UIPickerView that gets faded out to 20% alpha when not in use. I want the user to be able to touch the picker and have it fade back in.

I can get it to work if I put a touchesBegan method on the main View, but this only works when the user touches the View. I tried sub-classing UIPickerView and having a touchesBegan in there, but it didn't work.

I'm guessing it's something to do with the Responder chain, but can't seem to work it out.