Solution : https://service.sap.com/sap/support/notes/606359 (SAP Service marketplace login required)
Key words : 
$oracle_home/ocommon/nls_805/admin/data/oracle/805_32/ocommon/nls/admin/data/oracle/client/92x_64/ocommon/nls/admin/data, <oracle_home>/ocommon/nls/admin/data, \oracle\ora92\ocommon\nls\lbuilder\lbuilder, $oracle_home/ocommon/nls/lbuilder 18, imp sql loader database connections dbconnect, sap data dictionary automatically triples, registry underhkey_local_machine -> software -> oracle -> home, alter database character set <new_characterset>, subsequent read access operations, oracle requires essentially depend
Related Notes : 
       
| 1407071 | DDIC inconsistencies due to NLS_LENGHT_SEMANTICS = CHAR | 
| 1319517 | Unicode Collection Note | 
| 998399 | Changing the Oracle Instance Client from Lite to Full | 
| 886784 | Updating to Kernel 640 when using multibyte charactersets. | 
| 858869 | Desupport of multibyte character sets as of Oracle 10g | 
| 808505 | Secondary connections to Oracle database | 
| 695899 | Multibyte character set in SAP-R/3 | 
| 669902 | Setting the national character set to UTF8 | 
| 658322 | Composite SAP Note: Incorrect resulting set with Oracle | 
| 653690 | Composite SAP note: ORA-24365 | 
| 638357 | Transport between Unicode systems and non-Unicode systems | 
| 602843 | Environment settings for R/3/Oracle on UNIX | 
| 592657 | ORA-12701/ORA-12705/ORA-12709 | 
| 556232 | Environment settings for R/3/Oracle on Windows | 
| 518241 | DB Connect in BW for an external Oracle database | 
| 456968 | Changing Database Character set - Valid Superset definitions | 
| 393620 | Problems through incorrect ORA_NLS33 | 
| 323151 | Several DB connections with Native SQL | 
| 180430 | Installing the ORACLE client software for UNIX | 
| 112561 | Different character sets after 4.0X installation | 
| 102402 | Changing the database character set |