I don't think you have a square tube bumper on the X17Z do you? I thought the 17 came with the same thin C-channel bumper as my 23B. Even if you have the square tube bumper, I wouldn't mount anything to it as I have heard too many horror stories of bikes flopping around, ripping the bumper completely off the trailer and leaving it and the bikes in the path of oncoming traffic. Liability issue.
2006 23B Hybrid with 10k round bar WDH
2011 F150 4x4 SCREW Ecoboost, Max Tow, Integrated TBC, 3.73 LS axle, Firestone Ride Rite airbags.