HI JessS
With respect, post by Tracey_H should read 'and how MYOB's STP Phase 2 product needs to integrate with the ATO' not 'and how STP Phase 2 needs to integrate with the ATO.'
STP Phase 2 does not need your file online, there are many offline STP Products for Phase 2. MYOB has decided to build their STP Phase 2 in such as way as to require all users to put their files online. This is not an ATO directive, just a MYOB choice.
See this post for more detailed discussion including option to report STP Phase 2 without having your file online.
Regards
Gavin