[R-sig-Geo] drawing order in spplot, sp.layout

[Patrick Giraudoux]

Dear listers,

I am messing with spplot trying to get layers in the right order. 
Basically I want a SpatialGridDataframe overlapped with a 
SpatialPolygons object (actually a SpatialPolygonsDataFrame object). The 
the data attribute of the SpatialGridDataFrame has 13 columns (12 months 
+ the annual average of temperature). So, I expect 13 lattices panels 
corresponding to each.

This gives:

addCh<-list("sp.polygons",chinaUTM47,border="grey50")
spplot(ChinaTempTT,col.regions=mypal,sp.layout=addCh,as.table=T)

Unfortunately, in each panel:

- the polygons are drawn first and then are covered by the the grid (the 
reverse of what I want to). Thus polygons are invisible.
- the argument border="grey50" does not seems to used

Any hint ?

Patrick