Answer is there is no way to actually void a DD and update the ACH file.
The issue is the ACH tables get updated when you POST your payroll and those are set in stone; so voiding does nothing to the actual ACH file, or create a negative amount.
The only way to do this is void the entire pay run and re-enter, re-run and repost to create a new ACH file. There is a product suggestion on the connect site that I would suggest you and your clients vote for that would allow you to void a DD then create an ACH file with out the voided DD in this.