BEIJING/HONG KONG (Reuters) -China is pushing China Huarong Asset Management Co to sell non-core assets, two people involved in the revamp told Reuters, while considering offering an implicit guarantee of the liabilities of the debt-laden bad-debt manager. The plan, one source said, envisions the authorities informally backing $20 billion of dollar debt coming due this year for the sprawling company, one of the nation's four giant state-owned asset managers. Huarong's problems spooked investors in China's dollar-bond market in April after it delayed its business results, prompting ratings downgrades, warnings from global agencies and an ongoing suspension in share trading.