How to bring motion blur with shape into nuke?

Hi I am making roto’s in mocha and wish to export the shape and motion blur into nuke, I am having trouble exporting the motion blur. I am using mocha pro 3.1.1. and export shape data “nuke rotopaint” is there anything I am doing wrong?

Thanks in advance!

You’ll have to calculate the motion blur using nuke OR you will have to render the shapes out with motion blur as black and white mattes from mocha Pro.