Full Name email reply

[mopa]

Can someone tell me how the system works.

We just started using our eSupport this monday and have a lot of customers.
All of them have an email (obviously) and a name.
But the system only get the name from some of the customers:

First_Last@customer.com - First Last

But most of the customers are listed like this in "Users" -> Manage Users

First_Last@customer.com - First_Last@customer.com


This means that we sent them a reply with the below code:
<{$ticket[fullname]}>

The mail will say:

Hi First_Last@Customer.com


Instead of :

Hi First Last


I have even tried to change the Full Name of one of the customers but when sending a reply it still use her email as her name.

How can this be fixed?