In regards to Test debuts, the new Wallabies second-rower Dean Mumm could not have been given a more formidable assignment.

Not only does the latest Sydney University Test star have to take over the demanding duties of replacing the injured Nathan Sharpe, and conduct the Australian lineout calls, he also has to keep at bay "the Caveman" — French second-row opponent Sebastien Chabal.

This is a list of duties that would daunt the most experienced of Test campaigners. But for Mumm, who has been involved in two Tests only from the bench, they are responsibilities that he is relishing.

On the eve of tonight's second Test at Suncorp Stadium in Brisbane, Mumm was vibrant, and clearly not overwhelmed that Wallabies coach Robbie Deans had so much respect in him to pass on the important lineout calling duties to someone in only his second season of major football.

As far as Deans is concerned, Mumm's the word.

Deans said yesterday he had absolutely no qualms about piling the responsibilities onto Mumm, whose grandfather was a 1949 All Black representative.

"Dean has a background in doing that (lineout calling). It's not as if we're asking him to do something he's never done, or can't do," Deans said. "He'll be fine."

But the background is not exactly extensive. At the Waratahs, Dan Vickerman has been the main lineout caller. With the Wallabies, it has been Sharpe. The last time Mumm was the lineout architect was with the Sydney Fleet during last year's Australian rugby championships.

This relative inexperience still does not daunt the 24-year-old Mumm.

"This is something I'm really looking forward to, because it is a great responsibility," Mumm said yesterday. "To be able to control one area of the set-piece is a big challenge, but one I'm really looking forward to.

"The past few weeks it had been alluded to me that if Nathan needed to be replaced during a Test, I would be doing the calling. So I've had that in my mind the last two Tests that if need be, I would be calling the lineouts. When I was told yesterday, it wasn't a great shock."

Then there's the extra task of taking on the Caveman. Mumm immediately brightened when that name was mentioned. "I can't wait for that to be honest," Mumm said.

"It's going to be a bit of fun. Obviously he's quite a personality in world rugby. He seems quite a quiet bloke, but he certainly goes well on the field."

Sitting next to Mumm was the injury-shackled but still fiery Queensland forward Hugh McMeniman, who has moved onto the bench because of Sharpe's unavailability.

He is another who having played against France knows all about Chabal.

"You have to watch out for his aggression, because if he (the Caveman) gets a hold of you in a bad position, he'll make the most of it," McMeniman said.

"And at the bottom of the ruck he will make the most of it as well."

Yet that is not the only area where Mumm and co believe France will try to provoke them.

"There's no doubt that they will have a go at us, and target us up front," Mumm said. "They've got nothing to lose and will throw everything at us. They'll have a real go. So it's up to us to look after our own game, control our set-piece, and see what happens."

Deans is as cautious about the French. "It's pretty evident they didn't enjoy the first outing. So they will be physical."