The seeming lack of white balance info is something of a problem. As far as I can tell, there's no way to find absolute color temperature info in either the RAW file or the JPEG.
The camera must "know" the "as shot" temperature so it can process its sensor data into a color-corrected JPEG. Has anyone found out how to access that info?
Looking at the source for DNG24S-2, I noticed that it used Adobe's DNG software developer kit. If you get a copy of the SDK from Adobe, you'll find a binary called dng_validate (Windows and Mac versions provided).
I took a RAW+JPEG pair from my A710, ran it through DNG4PS-2, and fed the resulting DNG file to dng_validate. It gave me this warning:
*** Warning: Neither AsShotNeutral nor AsShotWhiteXY included (legal but not recommended) ***
Providing that info would seem to be the key to embedding "as shot" color temperatures.