There is no requirement to register with the software id, our software uses a different technology and it happens automatically when STP files are submitted. We fall into this category, that is described on the ATO website:
"Another option is your software may connect to the ATO through a sending service provider (SSP). If this is how your software connects to the ATO, you do not need to contact the ATO to set up a connection. Your SSP will do this for you."
So you are immediately able to create payslips and send STPs files with out any extra registration steps.