Solution : https://service.sap.com/sap/support/notes/834077 (SAP Service marketplace login required)
Key words : 
profile parameter rdisp/plugin_auto_logout, cst patch collection 15 2005, kernel patch, kernel release 640, session timeout, icf service, services based, kernel patches, overridden, prerequisites
Related Notes : 
       
| 885580 | Integrated ITS: Configuration Parameters | 
| 834501 | CST patch collection 15 2005 | 
| 824554 | ICM and SAP Web Dispatcher Timeout Parameter | 
| 737625 | Parameter recommendations for the ICM | 
| 705013 | Timeout for ICF services based on ITS |