surface plot

hi,

i would like to work with sperical coordinates (r,theta,phi)and to
create a surface plot that corresponds to vector U=(Ur,
Utheta,Uphi)where
Ur=Ur(r,theta,phi)
Utheta=Utheta(r,theta,phi)
Uphi=Uphi(r,theta,phi)

theta=[0:pi]'
phi=[0:(2*pi)]'
r=[0:10]'

how should i do it ?
surf seems to work only in cartesian coordinates.

thanx.

christina
.