Thank you Brɨan for your quick answer.
Shame on me for not looking in my e-mail "Spam" folder... i had answers to my case there!
A few remarks:
- the support ticket status at https://hostedendpoint.spn.com/Support.aspx is misleading as it's stuck on "New" and i don't see the answers there
- the support e-mails say that i can see details if i connect to https://identity.symanteccloud.com/ or https://clients.messagelabs.com/ (which seems to redirect to the same address anyway), however my credentials are not accepted there and i don't receive the password reset e-mail (yes, i check my spam folder this time)
- thankfully, the e-mails from "enterprise_technical_support [at] symantec [dot] com" say that i can "Simply respond to this email with your solution confirmation or request for additional information."
- OT: the "other thread" i mention in my first post seems to have been deleted, but i don't know what i did wrong
If i receive answers to my e-mail, i will mark this post as solved - SOLUTION: look at your spam folder, d'oh ;)
But meanwhile, i am interested in how i can connect to https://identity.symanteccloud.com/