The UV European FEL at ELETTRA: towards compatibility of storage ring operation for FEL and synchrotron radiation by De Ninno, G, Trovo, M, Danailov, M, Marsi, M, Karantzoulis, E, Diviacco, B, Walker, R, Bartolini, R, Dattoli, G, Giannessi, L, Mezi, L, Couprie, M, Gatto, A, Kaiser, N, Gunster, S, Ristau, D