MAFileDescription error

Hi, i work with squeak update to the last 2.9 seaside and Magritte-All-lr-269. I have a class 'MAArticoloModel ' defined with some descriptions. One description is based on MAFileDescription descriptionPicture ^ ( MAFileDescription new) autoAccessor: 'immagine'; beRequired; label: 'Immagine'; priority: 60; yourself Now when update an item with : self call: ( anMAArticoloModel asComponent) readonly: false; addValidateForm; addMessage: 'Update item; yourself all work fine. But when display an item with: self call: ( anMAArticoloModel asComponent) readonly:true; addForm: #(cancel); addMessage: 'Display item'; yourself i found the error: MessageNotUnderstood: WAMimeType >> copyUpTo. Any pointers would be greatly appreciated! Thanks! Dario