No idea about doing it as part of ZABO install (we don’t use that functionality here) but the best way I’ve found for installing add-ins is using a .reg registry modification, to point to the add-in location on a networked drive somewhere (that the user has access to, obviously)
REGEDIT4
[HKEY_LOCAL_MACHINE\SOFTWARE\Business Objects\BusinessObjects\5.0\BusObj General Preferences\busobj\Options\AddIn\This is the addin name]
"Description"="This is a description of the add in that is shown in the add-in window-"
"FileName"="\\\\file_server\directory\to\addin\addin.rea"
"Installed"=dword:00000001
NB this registry entry will apply to all BusObj users on a machine; there is a seperate tree for user-by-user config.