Another source of information on go-around mode is from a book- 'Automatic Flight Control' by Pallett. This states that go around mode can be engaged when rad alt is less than 2000ft and autothrottle is engaged. In the same paragraph he also states that a single press of the TOGA switch initiates a reduced thrust go around and a double press of TOGA initiates go around with full thrust rating.
Could any body shed any light on which particular type of aircraft he may be referring to, or is the information he gives fairly standard amongst the variants?