By Joseph Ax NEW YORK (Reuters) - Because the sums were large and such attacks are relatively new, the two Middle East banks hit in a $45 million ATM heist face an uncertain path in trying to recover their losses, financial, insurance and legal experts say. Oman-based Bank of Muscat lost $40 million and United Arab Emirates-based National Bank of Ras Al Khaimah PSC (RAKBANK) lost $5 million in the global heist, U.S. prosecutors said on Thursday. Hackers gained access through third-party companies that processed transactions for prepaid debit cards issued by the banks, the prosecutors said. ...