I use this technique:
I don't like maintaining separate .exe's on the server for these type issues, so instead, in my applications startup program, I have:

LPARAMETERS lnAppMode
lnAppMode=VAL(TRANSFORM(lnAppMode))

and then I conditionally do different things based on the value of lnAppMode. In this way, I'm not maintaining different .exe's but I can extend functionality for async processes.

Now just call your own exe like this:
lcFile='c:\mypath\mypath.exe'
lcParms='1'

! /N &lcFile &lcParms