Solution : https://service.sap.com/sap/support/notes/538081 (SAP Service marketplace login required)
Key words : 
profile parameter slic/high_available, patch level 251this mechanism, 162in lower patch levels, netweaver04 high availability  capabilities, digitally signed license keys, message server reason, conceivable message server, high-availability scenarios, high-availability saplicence, permanent license key
Related Notes : 
       
| 1008174 | CST Patch Collection 51 2006 | 
| 803018 | Central note for NetWeaver04 High Availability capabilities | 
| 542521 | CST Patch Collection 31 2002 | 
| 181543 | License key for high availability environment |