[R] Sweave in R 2.13.1 doesn't support cp1250 encoding

[Tomaz]

I upgraded R on windows xp from 2.12.2 to 2.13.1 and now I can not process Rnw
files with windows cp1250 encoding. Sweave complains: 

    file.Rnw declares an encoding that Sweave does not know about

What can I do beside downgrade R? When will Sweave support more encodings?
Has anybody found a solution?

Regards,
Tomaz