Solution : https://service.sap.com/sap/support/notes/1389108 (SAP Service marketplace login required)
Summary : 
      SAP R/3 Enterprise Extensions, part of the SAP Enterprise Core, can be optionally activated using the cross-client activation switch in transaction SFW5. From Release 4.7, the specific functions within Enterprise Extensions like EA-PLM become available, enhancing flexibility. Post Release ECC 6.0, additional optional functionalities are accessible in Enhancement Packages. To implement these features, activation of EA-PLM switch, starting from Release 4.7 x 1.10, and PLM Extension business functions from ECC 6.0 EHP2 are prerequisites. Users should refer to the attached documentation for specifics on activating and using EA-PLM business functions.
Key words : 
cross-client activation switches, terms ea-plm, plm extension reason, ea-plm switch, sap enterprise core, /3 enterprise extension set, activating ea-plm, activation switch, plm extension, enterprise extension
Related Notes : 
       
| 1049251 | Activate Enterprise Extensions in the switch framework | 
| 816806 | SAP ECC 5.0 Enterprise Extensions: Activation switch | 
| 666925 | SAP R/3 Enterprise Extension Set 200: Activation switch | 
| 658351 | SAP R/3 Enterprise 47x200: Software architecture/maintenance | 
| 588364 | Prerequisites for activating extensions | 
| 538887 | SAP R/3 Enterprise 47x110: Software architecture/maintenance | 
| 535003 | SAP R/3 Enterprise Extension Set 1.10: Activation switch |