Solution : https://service.sap.com/sap/support/notes/588480 (SAP Service marketplace login required)
Key words : 
rtl-enabled web browser displays rtl-languages, note concerns unicode-specific release restrictions, dedicated front-end code page, front-end code page installed, front end restrictions mentioned, bw/unicode requires version 9, bw bex front end, japanese texts/text elements, saving queries orweb templates, general restrictions unicode generally
Related Notes : 
       
| 1319517 | Unicode Collection Note | 
| 939404 | Unicode characters in Web template on Citrix | 
| 643813 | Composite SAP note - BW Unicode | 
| 589701 | Known errors in BW 3.1 Content Unicode | 
| 587150 | Support of Arabic-script languages | 
| 540911 | Unicode restrictions for R/3 Enterprise, ECC 5.0, ECC 6.0 | 
| 379940 | Unicode based mySAP availability | 
| 79991 | Multi-Language and Unicode support of SAP applications |