Army prosecutors said they were barred from discussing the case.
The major testified under a grant of immunity from Army prosecutors.
The guilty verdicts came after less than four days of testimony, in which Army prosecutors built their case on circumstantial evidence.
Army prosecutors said that he sought to align himself with Islamic extremists.
To level such a charge, Army prosecutors must have evidence that a soldier is frightened and misbehaves because of that fear.
In return for the stipulation, Army prosecutors had dropped several counts that knocked two years off the maximum six-year sentence.
Lieutenant Colonel Child, the Army prosecutor, did not object to the line of questioning.
Before that he was an Army prosecutor at Long Binh.
Under the agreement announced today, however, the general's lawyers and Army prosecutors have already agreed to limit his sentence.
The sergeant major has denied the charges, insisting that Army prosecutors were motivated by racism to bring the cases against him.