An SDR is not needed to receive and demodulate DRM. All that is required is that a wide enough unfiltered bandwidth be converted to a low enough frequency for the sound card to work with.
I have never done DRM with the RX320d myself, but it is specifically advertised as being capable of DRM work, with a sound card and the correct software. It has a 12 kHz IF for this specific application.
So the answer probably is yes, you can do what you ask. If you Google "12 kHz DRM Decoder" (without the quotes) you will find a few examples of people doing the same thing with various rigs and 12 kHz IF's. It appears that the software DREAM will work to demod the DRM, and I suspect there are others.
T!