change how joomla make the user name

-- HikaShop version -- : 2.6.4
-- Joomla version -- : 3.6.5

HelloMy configuration for the fields registration is
address_firstname = name
address_lastname =surname
address_middle_name = name company

Now when user receive the email for the confirmation registration it shows hello dear "name+name company+ surname" and it is not very cool
That is couse the name user in joomla is composed of name+name company+ surname
It should be better name+surname+name company
Do you know how to change that??
Can I change the way that joomla make the name of usder from the hikashop fields?

Thanks
Frank

Thanks fro your replay

I changed the code in this way:

$this->registerData->name = @$addressData->address_firstname.(!empty($addressData->address_middle_name)?' '.$addressData->address_lastname:'').(!empty($addressData->address_lastname)?' '.$addressData->address_middle_name:'');

Hello
How can I reach the same goal with hikashop 3.0
I see that that the file user.php in administrator/components/com_hikashop/classes/ is different fron the previus

THanks
Frank