Same way you set up any other SHOUTcast stream. Just make sure that "Make this stream public" is not checked on the Yellow Pages section of the SHOUTcast DSP.
Also, the SHOUTcast DNAS (Server) is just there server, it is not the DSP as well. It is two different downloads.
Need SHOUTcast help? Read me before posting...
Read the tutorials there on help setting up a stream.