[R] Change panel background color in spplot()

[Marcel J.]

Hi!

How does one change the background color of the map-panel in spplot()?

Example:

library(sp)

data(meuse.grid)
gridded(meuse.grid) = ~x+y

spplot(meuse.grid, "part.a")

How would I get another background-color for the map-panel (but not for 
the whole plot) here?

Thank you!

Marcel