I have no clue about DNG4PS-2, but white balance support for A570IS is missing from dcraw. For me, it detects the raw file as A620 and the resulting white balance is not good even though the image itself is converted otherwise properly.
dcraw's home page has some info about submitting RAW files for new cameras, that should probably be done. It'll take a while before I can give it a try as direct sun light is needed and we don't really get much of that around here this time of year.
Anyway, I did make a quick and dirty first try using a white card raw image and 'dcraw -v -A'. Then using the resulting coefficients, running dcraw with
-W -r 2.125 1.0 1.71 1.0115
worked way better than without the correction.
