No one doubted that Tate and his 38 comrades in the 2nd Defence and Employment Platoon had fought bravely for the five weeks of its existence.

But doubts persisted for almost four decades about whether the men were a platoon, an assault group or a discrete infantry group.

The men who served insist they were a platoon.

The author of the official history of Australia's involvement in Vietnam, Ashley Ekins, said the memorial's position on the outfit's non-status as a platoon had not changed, despite government recognition.

''They were not a 'phantom' platoon: they were an ad hoc squad put together to work with armour. They were just one of many ad hoc groups,'' he said.

To set the record straight as he saw it, Tate spent four years writing a book, The War Within, which had its Canberra launch yesterday.

The book covers Tate's 212 days in Vietnam, two years recovering from a war injury, periods of sexual and alcohol abuse and his involvement with the 2nd Defence and Employment contingent.

For all the debate over its name, the 2nd Defence and Employment was a crack group of soldiers.

''We killed more Viet Cong in five weeks than most platoons did in a year. But still they disbanded it, because they didn't want to admit it,'' he said.

''It'' was the mistreatment of the Viet Cong soldiers' bodies.

According to Tate, men of the 2nd D&E blew up some enemy corpses, strapped others to the back of an armoured personnel carrier and dragged them to a nearby village.

''We were instructed to do it. As we understand it, there were communications between Australia, the high command in Vietnam and the leader of the force out in the bush, out at Thua Thich.

''We cannot get those communications from the War Memorial. In fact most of the material we found we had to find ourselves, and most of the stuff we found to prove [we existed as a platoon] was right under their noses all the time.''

But times change, and on May 29 Tate and other veterans met the parliamentary secretary for defence support, Mike Kelly, and said later he had formally acknowledged the platoon's existence.

Another veteran from the unit, Ted Colmer, said he was ''deeply insulted'' by the War Memorial's refusal to give the platoon's existence public acknowledgment.