Hello;
I don't know exactly what you mean by down counter, but if you want to implement a sort of frequency divisor, you can refer to the "Generate Pulse Train on Freq_Out.vi" Labview shipping example. That VI will divide the chosen timeBase frequency and output the result pulse train at the FREQ_OUT pin.
You can also refer to the Pulse Train Generator.vi if you want to use the counter output pin.
Hope this helps.
Filipe