The netsh command wants an appid (see here) :
netsh http add sslcert ipport=0.0.0.0:8000 certhash=0000000000003ed9cd0c315bbb6dc1c08da5e6 appid={00112233-4455-6677-8899-AABBCCDDEEFF}
I've not been able so far to understand how I'm supposed to know the GUID netsh wants me to provide. Any hints?
You can use any valid GUID. It is only used to allow you to identify the binding later.