Yes. In the Transmit section, you need to send the original RAW files and not save as JPEG. If you choose to save as JPEGs, then the previews in your RAW files will have to be used because it can't render your RAW files.
If you can't upload RAW files, then I suggest either rendering your RAW files to JPEGs with your favorite RAW converter, or shoot in RAW+JPEG mode and send the JPEGs only.
-Kirk