basemap: avoid thin line at end/beginning of data on orthographic projections?

Hello list!

Is there a way to avoid the thin line at the end/beginning of data when
using an orthographic projection? With other projections or when no pole
is visible, the line can be hidden by shifting the data grid (as done in
the example), but if you have to have one of the poles visible, I don't
know how to get rid of the line.

Example (modified from examples):

from matplotlib.toolkits.basemap import Basemap, shiftgrid
from pylab import *

# examples of filled contour plots on ortho projection.

# read in data on lat/lon grid.
hgt = load('500hgtdata.gz')
lons = load('500hgtlons.gz')
lats = load('500hgtlats.gz')

# shift data so lons go from -180 to 180 instead of 0 to 360.
hgt,lons = shiftgrid(180.,hgt,lons,start=False)
lons, lats = meshgrid(lons, lats)

# setup of orthographic basemap
m = Basemap(resolution='c',projection='ortho',\
ax = fig.add_axes([0.1,0.1,0.7,0.7])
# make a filled contour plot.
x, y = m(lons, lats)
CS = m.contour(x,y,hgt,15,linewidths=0.5,colors='k')
CS = m.contourf(x,y,hgt,15,cmap=cm.jet)
cax = axes([l+w+0.075, b, 0.05, h]) # setup colorbar axes
colorbar(drawedges=True, cax=cax) # draw colorbar
axes(ax) # make the original axes current again
# draw coastlines and political boundaries.
# draw parallels and meridians.
#parallels = arange(-80.,90,20.)
#meridians = arange(0.,360.,20.)
title('Orthographic Filled Contour Demo')