Solution : https://service.sap.com/sap/support/notes/1094923 (SAP Service marketplace login required)
Key words :
tree -> topology -> defaults -> index -> parameter, trex admin tool, index-settings, terms trex, trex recognizes, trex conifguration, trex server, speicial character, special character, token_separator entry
Related Notes :
| 1003900 | TREX 7.1: Central note |