A/A B/* C/* D/* P/* si/si, or
A/a B/* C/* D/* P/* si/si
"Ground colour should be rich golden brown as in the agouti. Undercolour to be blue-black. Eye black. The silvering should be even throughout, carried well onto the feet."
Breeding information below the picture.
Silver brown is by no means popular anywhere. There is even debate on what this colour is genetically! Some say it's silvered chocolate, others go for silvered agouti or cinnamon. However, only silvered agoti would give the required undercolour. So, I'd say this theory is wrong and a silvered chocolate is simply silver chocolate.
In order to get any of these, one should introduce the recessive silvering gene (usually from silver grey) to agouti and then proceed according to the breeding methods of agouti with extra attention given to silvering. When breeding any of the silvered varieties, it should be remembered that the silvering develops with age. The mice look "non-silvered" at first and develop the silvering from the belly up since 7 or 8 weeks of age. It is important for the breeder to keep all babies until that age, or she might end up having nothing but un-silvered mice... Key thing is selecting as silvered mice as possible for future breeding. Breeding silver brown is, to say the least, time consuming but when the breeder finally gets them it is really rewarding.