Originally Posted by NorthPentax 
My problem is that DxO don't work after I have imported in to LR with the compressed DNG.
So I don't compress DNG now. Problem solved.
My second problem is that it's easier to pick and reject my images with LR and then use DxO.
DxO doesn't work this way. DxO first then LR2. I'll find a way.
just do not use .DNG - use .PEF... .DNG does not offer you any real advantages and just gives you less freedom w/ raw converters... .PEF is supported in full by more raw converters than .DNG, as you can see yourself... as for the using DxO as a raw converter from LR - you can do this as long as:
1) DxO will accept the full filename of the raw file as a command line parameter.
2) your raw file will be in the filesystem and not in LR database.
3) you will write and compile a simple program that accepts the command line parameter containing the name of TIFF file from LR and then starts DxO after replacing the extension in that command line parameter with ".pef" for DxO to process it.
4) that program is set in LR as an additional external editor.
5) you will overwrite the original TIFF file generated by LR, which will be thinking that you actually edited it (instead you will do a raw conversion w/ DxO).