Solution : https://service.sap.com/sap/support/notes/939404 (SAP Service marketplace login required)
Key words : 
\programme\sap\frontend\sapgui, unicode-enabled operating systems, citrix/windows terminal server, bex web application designer, terms windows server 2003, bex front end 3, -unicode back end, unicode back end, standard character set, solution import bw 3
Related Notes : 
       
| 874828 | SAPBWNews for BW 3.5 frontend patch 09 | 
| 588480 | Release restrictions for Unicode in SAP BW 3.x |