I Lost My Combination

I Work at Ethiopian Electric Power corporation.we Have a Bumil Safe Sd-104 in Our office.our Office Bought the Safe Second hand.now the Sd-104 Is Closed and We Could Not Open it.the Combination Numbers Are the Default Combination Numbers Found in the manual.but Unfortunately the Manual Is Also Locked Inside with Other Financial documents.so Anybody Who Can Help Me Crack the Combination and Open My Safe