UPDATE 1-Unicredit says aware of Fortress proposal for Popolare Vicenza

CERNOBBIO, Italy, April 8 (Reuters) - UniCredit is aware of a proposal by U.S.-based Fortress Investment Group to buy into a 1.8 billion euro ($2 billion) share issue the Italian bank is guaranteeing at smaller rival Popolare di Vicenza, but has no say over it.