McManus is credited with establishing Interwoven in the Asia-Pacific region and is said to have been "personally invited by the Interwoven senior management team to return to head up the business locally".
He originally joined the company in 1998 and then left to return to the United States.
"I am delighted to return," he said in a statement today.
In other news, Software AG announced the promotion of Stuart Rees to vice-president of Australia and New Zealand.
Rees was formerly sales director for the internal webMethods business division and has held sales management roles with IBM in Australia and the UK.
Steve Keys, formerly sales director for the enterprise transaction systems (ETS) business division at Software AG will now cover Rees' former role in addition to his own.