Solution : https://service.sap.com/sap/support/notes/1842704 (SAP Service marketplace login required)
Key words :
schema version = 2 mimetype = text/xslt class = crm_svy_transformation short description = generate bsp template, /ncrm_survey_suite -> survey repository -> cat server -> administer -> select rfc destination -> clear cache, software component bbpcrm bbp / crm, cat server cache, select survey->generate, escaping properly line breaks, updated xslt file, generate multiple surveys, select 'display versions', select 'generate'