Tua and Cameron have been indelibly linked since their brutal and one-sided fight ended in a dramatic second-round knockout victory for Tua in Hamilton four years ago following a bitter build-up between the pair.
Schuster wasn't in Cameron's corner for that fight, but has been involved in many others. Now he is helping Tua prepare for his heavyweight battle against Belarusian Ustinov at Claudelands Arena on November 16 after Tua parted company with Australian Dave Hedgcock following his calf injury.
Cameron's manager Ken Reinsfield said Schuster recently sat down with him and Cameron and asked for their blessing to help Tua, a request which was quickly answered in the affirmative.
"People might think it's unusual but at the end of the day it's a business. Henry is a professional boxing trainer. Sure, Tua and Shane fought one another [but] whatever was done was left in the ring.
"There's no animosity from Shane towards David and vice-versa. David wished him all the best when he was fighting Danny Green for the world title. A lot of the animosity is made up by other people."
Cameron, fighting as a cruiserweight, lost to Green by unanimous decision in Melbourne in November.
It was a tough loss for Cameron to take and he hasn't fought since. However, Reinsfield said he was working on a new fight and was hoping to be able to announce the details soon.
Tua's promoter Dean Lonergan, of Duco Events, said he was relaxed about his fighter parting ways with Hedgcock.
"David has to do what makes him comfortable. Just looking at the shape he is in, his mind's in the right place and his body is 100 per cent in the right place," Lonergan said.
