HI @Christophe_Bock Im not expert on Fonts but I have recently published video about Ligatures and IMO with applying different CSS provided by Fonts creator new glyphs should be displayed. As this is about custom code not WF you should start searching internet about how to and try to apply process in WF. here is one answer but feel free to find another responses to get better understanding of this process.
In this request is the video I have mentioned.
Hopefully it will point you right direction