You won't be able to import a vector path into the vertex modeller because it can't handle Bezier curves. The only way is via the spline modeller. I have the same problem with the keyboard shortcut for Move. I also had a problem with the Link shortcut but that disappeared for some reason I don't remember. It's a shame that Carrara doesn't have a way to change the keyboard shortcuts as is [was?] possible in Amapi. Perhaps you should try Amapi ... the NURBS handling may be exactly what you're looking for. ;-)