Nurbs stands for Non Uniform Rational B-spline. Metanurbs are calculated differently from nurbs.
Lw doesn't support them basically because of tradition. It's never had them and previous teams never decided they were useful for the cost of putting them in I guess. Maybe the new team will.
You do have access to splnes and can extrude etc these, which you could then metanurb, it's up to you
__________________
Push the software, don't let it push YOU!
My own plugins and work:
www.mikegreen.name
LaptopSetup:corei5 2.26GHz nvidia 230M 4Gig win7
HomeSetup:4 Ghz P4 3GigRam FX9600 WinXp