Set the widelux to 1/15th, which actually takes over 3 seconds to complete the exposure. Compose the image with the subject on the left side (where the lens starts). Once the lens swings past the subject, quickly recompose so that the subject is on the right side. It's just a matter of swivelling the camera very quickly at the right moment, and changing where it's aiming. I'm sure it's the kind of thing that gets easier with practice.