Retrieving user header from its call number

Hi,

first of all here is how our users are created :

[user001]
type=endpoint
context=from-internal
disallow=all
allow=ulaw
callerid=John Doe <334>
auth=user001
aors=user001

[user001]
type=auth
auth_type=userpass
password=mypassword
username=user001

[user001]
type=aor
max_contacts=3
remove_existing=yes

Is there a simple way to retrieve user01 from 334 ?

Thanks a lot !

For the time being, we only find a solution with database
we are writing into database : 301 is user001, 302 is user002…
and then we can retrieve the userXXX with its exten

The problem is that we have to populate the database and i was hoping there was an embeded command that directly retrieve the userXXX from exten