lines in 3d-cloud plot (lattice)

Hi all,

I'd like to plot a set of data (x,y,z) as 3D-cloud, and add several line 
plots to the same 3D graph:

Two questions:

1) How do I connect points to get a line?

cloud(z~x*y,data=d,zlim=c(0,1))        # works
cloud(z~x*predict(l),data=d,zlim=c(0,1),type="l")   # type="l" doesn't

Warning message:
type = l not implemented, consider using 'panel.3d.cloud = panel.3dscatter.old' in: panel.3d.cloud(x = x, y = y, z = z, rot.mat = rot.mat, za = za,

help.search("panel.3d.cloud") also didn't report any hits.

2) How do I superimpose a second data set onto the same graph?

(something equivalent to the sequence plot(), followed by points() or lines() in the base plotting functions)

Thanks for any help

Pascal