Mbox 3rd gen and piezo pickup

[andyonio]

I have bought a 3rd gen Mbox.
I want to record my nylon strings classical guitar.
I have a piezo pickup that sounds good when used with my stand alone ampli.
This is my pickup:

http://www.kremonausa.com/en/pickups...pickup-kremona

I am not able to record my guitar with protools 9 (bundle) when I plug the piezo pickup directly to the guitar front input of the Mbox. Very low level and high distortion.
The mbox input impedance is 1 MOhm. Do I need a preampli or is there a impedance mismatch? Which settings should I use in protools?
Thanks.