An Australian cowboy who converted to Islam and allegedly fought for the Taliban (search) in Afghanistan went before a U.S. military commission Wednesday and pleaded innocent to war crimes charges.

Lawyers for David Hicks (search) also challenged the impartiality of four members and one alternate. It was the second attack on the commission's ability to be fair since arraignments began a day earlier.

Hicks, 29, in dark gray suit and tie, sat expressionless while listening to charges — including conspiracy to commit war crimes, aiding the enemy and attempted murder for allegedly firing at U.S. or coalition forces — carrying a possibility of life in prison.

"Sir, to all charges, not guilty," Hicks said, then breathed a huge sigh. He smiled after the five-member panel rose to conclude the hearing. It set his trial for Jan. 10.

Seventeen motions by Hicks' defense team are to be decided by Nov. 2, including an assertion that he should be considered a prisoner of war and not an "enemy combatant," which gives him fewer legal protections.

Captured in Afghanistan, Hicks arrived at Guantanamo Bay (search) in January 2002 as a slight, baby-faced 26-year-old. At Wednesday's hearing he looked considerably older and stern.

It was the first time his family had seen him in five years.

"My expectation was that we would have David back to Australia after the first three months," his father, Terry Hicks, 58, said after arriving Tuesday from Adelaide, Australia, with Hick's stepmother, Beverly. "I don't think it is a fair and honest system."

During two short meetings with his family, where David Hicks was shackled but not under guard, his father said he confirmed reports of abuse after his capture by U.S. troops. David Hicks also said he suffered mental abuse during his 21/2 years in Guantanamo Bay, Terry Hicks said.

"The first meeting was pretty emotional," the teary-eyed father said of his son, who has been in solitary confinement for months. "It's been hard on him."

He said he brought his son books and pictures. Much of the time was spent catching up, with David Hicks asking about his two children and his cousin's newborn, his father said.

"Our main aim is still to get him back to Australia," he said.

Joshua Dratel, David Hicks' lead civilian attorney, began the hearing by challenging the impartiality of the presiding officer, Army Col. Peter E. Brownback, a former military judge.

At the core of his argument is Brownback's relationship with John D. Altenburg Jr., a retired Army general in charge of the proceedings. Brownback was with Altenburg in Fort Bragg, N.C., and his wife worked in Altenburg's office. He also attended the wedding of Altenburg's son and spoke at a retirement roast for the general.

Dratel also questioned the impartiality of three other panel members and an alternate, and he argued that David Hicks should be considered a prisoner of war rather than an "enemy combatant," a status used by the United States that provides fewer legal protections.

Altenburg, the military appointing authority, will decide whether any commission members should be disqualified after reviewing challenges raised during this week's arraignments of four men.

David Hicks, who converted to Islam after fighting briefly alongside Muslims in Kosovo, went to Pakistan for further Islamic studies, then allegedly went to Afghanistan to fight with the Taliban. He is alleged to have shot at U.S. and coalition forces.

This week's hearings involving U.S. military commissions are the first such proceedings since German saboteurs were tried secretly during World War II.

Usama bin Laden's chauffeur, 34-year-old Salim Ahmed Hamdan of Yemen, declined to enter a plea at his hearing Tuesday, indicating he would wait until motions filed by his military-appointed lawyer are decided sometime this fall.

Hamdan's defense is challenging whether the hearing should proceed without a ruling on his "enemy combatant" status, which provides fewer legal protections than given prisoners of war.

That classification was used to justify trying Hamdan and others before military commissions, which will allow secret evidence and no federal court appeals.

Hamdan's defense attorney, Navy Lt. Cmdr. Charlie Swift, also has filed a federal lawsuit in Washington arguing that the commissions are illegal.

Human rights groups have said they doubt the commissions ordered by President Bush will be fair, contending the military officers hearing cases will not be independent.

The five-member panel will act as both judge and jury, and Brownback is the only member with formal legal training.

All four detainees with pretrial hearings this week face charges that could bring life in prison, though authorities say others could face the death penalty. It could be months before their trials begin.

The commission also will hear arraignments this week for Ali Hamza Ahmad Sulayman al Bahlul, 33, of Yemen, and Ibrahim Ahmed Mahmoud al Qosi, a Sudanese born in 1960.

Meanwhile, three U.S. defense lawyers — Brent Mickum, Gitanjali Gutierrez and Joe Margulies — have obtained clearances to travel to Guantanamo on Sunday to meet five prisoners who have pending court challenges, said Michael Ratner of the New York-based Center for Constitutional Rights.

They will be the first lawyers to meet detainees not facing formal charges. Ratner said the lawyers are under restrictions preventing them from speaking to journalists.