R help - Jul 2010 - print.trellis draw.in

I am attempting to plot a trellis object on a grid.

vplayout = viewport(layout.pos.row=x, layout.pos.col=y)

grid.newpage()
pushViewport(viewport(layout=grid.layout(2,2)))

g1 = ggplot() ...
g2 = ggplot() ...
g3 = ggplot() ...
p = xyplot() ...

# works as expected
print(g1, vp=vplayout(1,1))
print(g2, vp=vplayout(1,2))
print(g3, vp=vplayout(2,1))

# does not work
print(  p,
         newpage=FALSE,
         draw.in=vplayout(2,2)$name)

Error in grid.Call.graphics("L_downviewport", name$name, strict) :
  Viewport 'GRID.VP.112' was not found


What am I doing wrong?

Thanks!

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