SAO PAULO, Feb 5 (Reuters) - Brazilian fashion companies Arezzo and Grupo Soma said on Monday they had agreed a merger to form an entity with revenues of 12 billion reais ($2.42 billion) to be 54% controlled by Arezzo. ($1 = 4.9657 reais) (Reporting by Alberto Alerigi Jr.; Writing by Steven Grattan; Editing by Louise Heavens)