Solution : https://service.sap.com/sap/support/notes/686409 (SAP Service marketplace login required)
Key words :
port/sap/bw/mime/customer/path_to_mime/file, /sap/bw/mime/customer/path_to_file/file, port/anonbex/mime/customer/path_to_mime/file, /sap/bw/mime handler service, mime/customer/path_to_mime/file, /sap/bw/bex handler service, port/sap/bw/bex, incorporate customer-specific mimes, /sap/bw/bex, integrated mime objects
Related Notes :
994878 | Logon pop up appears if Role Menu web item is used |
632857 | Including MIME objects in BW Web Applications |
516884 | Anonymous logon with BW 3.0A/B and SAP Web App. Server |