Looking into the latest(?) update .GEL file (00.01.01.00.02) for the DS2000 series, I think the CAN decoder is already present and we just need to find the right bit to enable it:
Press this key or turn the Function knob to setup the CAN trigger's Speed as10kb/s, 20kb/s, 33.3kb/s, 50kb/s, 62.5kb/s, 83.3kb/s, 100kb/s, 125kb/s, 250kb/s, 500kb/s, 800kb/s, 1Mb/s or user.