You need a recent (preferably latest) version of MediaCenter and have the ASIO drivers installed from Teac (version 1.02 I believe). Older versions will have problems, see the link 6233638 posted. You can check in Add/Remove software if its installed, and in device manager you can see if the device is working properly (it will have a yellow question mark if it isn't).
In MediaCenter, open Tools/Options, Audio (pick the zone to configure at the top) and for Audio Device, pick "TEAC ASIO USB DRIVER [ASIO]".
Check DSP & Output format. Under Output format you can configure Output Encoding. If this is set to None and bitstreaming is disabled, all DSD files will be decoded to PCM and resampled according to the sample rate rules below Output encoding. If you set it to DSD or DoP, all DSD files will be decoded to PCM, processed by MC and decoded back to DSD to match the output settings. If you want DSD files to be left untouched by MC, you need bitstreaming.
The "problem" with bitstreaming however is that MC won't do any processing, not even replaygain to level the volume between tracks. If you like the sound of DSD, IMHO its best to enable DSD or DoP in Output format and let MC decode DSD to process it for volume control and output everything to DSD, even PCM. MC's audio engine is 64-bit and the process to decode DSD is effectively lossless.