and i'm trying a find another different way of explaining but i will soon need screenshots

Let's try this way :
- You're a proxmox administrator living in los angeles
- Alice, your friend, is an Icinga administrator living in New York
One day, because you are in a good mood, you decide to create a vm on proxmox called "Damned good Windows VM"
=> because my proposition has been accepted and implemented into proxmox, Alice will see in her Icinga monitoring panel, a new node appear and called "Damned good Windows VM" on which an automatic autodiscovery service is started. The discovered services are HTTP, HTTPS, SMTP, IMAP, LDAP in this example. As a result, these informations are given back and you in Los angeles, in front of proxmox, you see that your "Damned good Windows VM" is now populated with new information corresponding to the discovered services. You also could follow the provided link to go into Icinga and directly to the "Damned good Windows VM" node for the details.
This is a "add event", that is create a node on proxmox, Icinga is informed and start adapted process to give back results to proxmox.
There are other events in proxmox like suppressing a vm, renaming a vm.
There are other events in Icinga like services changing on a given node over time.
I don't know Icinga from a long time either, only 3 weeks ago. In my evaluations, i were more on the "new" kids on the block ZenOss, Zabbix... vs the old nagios but even if Icinga is among the ones based on nagios, i'm more and more in the process to forget ZenOSS and the others, so here is my suggestion also based on the fact that nothing like that has been implemented into proxmox or even announced and still represent a great potential added value close to a killing feature.