Solution : https://service.sap.com/sap/support/notes/959874 (SAP Service marketplace login required)
Key words :
enhancement spot hrrcf_correspondence -> badi hrrcf00_modify_html_mail, character sets utf-16be, understand utf character sets, html-based e-mails, system correctly displays umlauts, complete style information, display e-mails, <style></style> block, system code page, e-mail correctly
Related Notes :
| 1319517 | Unicode Collection Note |
| 1067171 | Sending modified HTML e-mails |
| 979922 | Correspondence: HTML mail and character format |