Want to be able to set reporter or have additional field

At SSI we have the following use case:
Someone with a problem calls into service, and service creates the bug/task in Jira and assigns the bug to a colleague who is working on the problem. So we have the following three roles:

• Caller / Describer (or whatever the name of the role is)
• Reporter (someone who creates the bug in Jira)
• Asignee (someone who fixes the bug)

All three want information what work is done on the task. Everybody is known as use to JIRA, but the caller/describer could also be an outside person.

Solution could be:
a.) I am able to set manually the reporter, so I could report a task in the name of someone else.
b.) I get an additional list selection for the caller/describer role