Closed for Company Meetings: Between September 18 (5pm PDT) and September 22 (12pm PDT), Support and Sales requests will be delayed. Only time-sensitive issues will be addressed during that time. Thanks for your patience.
I don't think software renderer supports nurbs, but you can of course capture to a texture and then go back to matrix format. Note that copying from gpu to cpu isn't ideal (but neither is software rendering, of course). Here ya go: