Hi Spence, thank you for your answer. I have finally found the solution to this issue. I have to use a SFP to HSSDC2 cable, which is part number 112-00082. So, if it helps:
ESH module to ESH module - PN 112-00049 HSSDC2 connector to HSSDC2 connector
ESH module to ESH2 module - PN 112-00082 HSSDC2 connector to SFP connector
ESH4 module to ESH4 module - PN 112-00084 SFP connector to SFP connector
Thank you so much for all your answers.