Hello Karlito,
I don't know what kind of board you are using but I assume its a multifunction daq board. As you allready did, you can create digital pulses using the digital output lines . but then the pulse width will allways have to be generated in software timing (with a wait function) . e-series boards does not support hardware timed digital output.
The most convenient way to generate a desired pulse would be to make use of one of the counters of the board. There are different examples showing how to do it (eg. gen dig pulse.vi). In this case you'll create a pulse on the output of the respecting counter.
I. Schumacher
Application Engineering
National Instruments