vectors of v and omega

[a.larkin@xxxxxxxx]

I have outputted horizontal velocity v and vertical velocity w from a fortran
program. I then used idl to convert the data into netcdf. When the data was
read into Ferret, three variables were displayed, v,w, and v,w. So it was 
assumed that these velocities could be plotted in vector format. However, 
the plot doesn't seem to know that v is horizontal and w is vertical and 
therefore plots everything on the same plane. Does anyone know how I can
tell ferret to treat these velocities in the same way as u and v are normally
treated? When I am converting the data into netcdf, do I have to specify the
planes that they are in as well as the fact that they are functions of latitude,
height and time.
Alice