Order number - Invoice number - Paypal

Order number - Invoice number - Paypal

Hello Team!

How can I edit/set the "invoice number" in Joomshopping.
I can only set the "order number" in settings.

SOMETIMES problem arises when people pay by Paypal.
Paypal does not use the "order number" but a different "invoice number". The two numbers are not the same.

Because we have 3 shops it happens that sometimes this "invoice number" has already been paid. And therefore is rejected.
I hope you understand what I mean.

How can I set the (invisible) "invoice number"? In Joomshopping or in Paypal?

Thank you

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Aw: Order number - Invoice number - Paypal

No configuration.
Need to change the code
components\com_jshopping\payments\pm_paypal\pm_paypal.php

<input type='hidden' name='invoice' value='<?php print $order->order_id?>'>

change to (example)

<input type='hidden' name='invoice' value='IN-<?php print $order->order_id?>'>