Yes that's what I use.
But then you can only select all DSD, DSF files, not DSD64, DSD128 etc... independently.
It would be the equivalent of saying, convert mp3 320 but not 128 for instance.
Since DSD files are not based on a frequency that makes sense for the DSP Studio (it's 2.8M, 5.6M, 11.2M not Khz) there is also no clear mapping with the option in DSP Studio to downsample the DSD256 or DSD512.
I know those are extreme cases; DSD256 and DSD512 (I don't own any of those) are overkill. But I own a few albums in that format/sampling rate (mostly Vinyl RIPs), so avoiding the conversion most of the time is preferable for the other files (DSD64 coming from my SACD Rips for instance).
I didn't find a way, so now I manually go in the DLNA server setup every time I play one of those files, and force the DSD/DSF conversion.
It's not ideal in terms of user experience.
And sure I could convert those files with probably no quality lose to my ears, but it's worth asking the developers of JRiver to see how easily it could be implemented.
Maybe something in the DSP Studio?