Hi There,
How you handle this situation can be pretty complicated, based on where the User/Domain information is being passed to and from.
Some of this can be handled by the Tuner (in the case it's just registry entries that it's based off of). You can find this out by just looking through the MSI tables with InstallShield's Direct Editor.
I suspect some other configuration you might be able to do with the Ini File Changes view of the editor project. But again, it depends on how this all gets built into the repackaged project file.
Worst case scenario, you can create manually custom actions to invoke scripts based on the %USERNAME% and %USERDOMAIN% environment variables.
Does this make sense at all in context? I've not repackaged Tivoli, so I'm not certain if my advice is valid as such.