SOMALIA'S Islamist insurgents are moving millions of dollars through the formal bank system and appear to be investing in businesses and real estate, according to a United Nations report offering a rare glimpse into their finances. Al Shabaab has for years been battling Somalia's internationally-backed government to impose strict Islamic law in the anarchic Horn of Africa nation. "Al Shabaab remains in a strong financial position and is generating a significant budgetary surplus, some of which is invested in property purchases and businesses in Mogadishu," said the report by the U.N. sanctions panel on Somalia. The report by the group,…