I’ve done something similar with the DSC integration. I had to edit the DH to add desired attributes in the metadata { } section.
It allowed me to use the virtual keypad attributes (such as READY, AWAY, STAY, TROUBLE, AC, etc.) in webcore instead of relying on SHM.
One practical use of this was to know when the system is ready (when all contacts are closed). Initially I had to check each contacts contact and each motion sensor motion. Now I can simply check DSC panel status.
As for Iris, I’m afraid I’m in the dark as I’ve never used them.
What you could do to figure something out is look into your device (panel) events in GRAPH/IDE and look at the columns “Name” and “Value”.
If you see what you need there, then try editing the DH by adding the following in the metadata section at the beggining of the file. It’s usually between capability and commands.
attribute "NAME_GOES_HERE", "string"
P.S.: This advice is most likely incomplete/insufficient as my knowledges are fairly limited in that matter.