Order Export QuickBooks plugin email field

-- HikaShop version -- : 2.5.0
-- Joomla version -- : 3.4.4

Regarding: Order Export QuickBooks plugin
This plugin is great.

There is one small problem.
I does not export the Hikashop customer e-mail adress.

The "email" field is empty in the exported CSV file, but all other fields like name, address, phone etc works fine.

In Hikashop=>configuration=>checkout I have the following enabled.
Default registration view: Guest
Registration: Guest
Display email confirmation field: NO
Ask address on registration: YES

Im not user is the plugin uses the "Joomla user e-mail"(I only use hikashop guest checkout) or the "hikashop costumer e-mail"

How can we fix this ?