I have noticed that when I create a custom AXI Stream bus in System Generator (using EDK pcore export flow), the tools automatically adds this line in the MPD file.
PARAMETER C_AXI_STR_FFT_OUT_PROTOCOL = XIL_AXI_STREAM_ETH_DATA, DT = STRING, ASSIGNMENT = CONSTANT, BUS = AXI_STR_FFT_OUT, TYPE = NON_HDL
An enhancement has been added to the EDK export settings Bus interface dialog in System Generator 14.6.
A new column named Bus Protocol has been added to allow user to specify the AXIS bus protocol. This parameter is will be translated to the pcore MPD file.
A windows 64-bit patch exists for System Generator 14.5 to enable this enhancement. See (Xilinx Answer 56214)