Showing WooCommerce order number in Sales order


I have connected ERPNext with WooCommerce and that is working fine. Orders from WooCommerce are imported into ERPNext.

One thing I would like to add to sales orders in ERPNext is the order number that is used in WooCommerce. There is already a Woocommerce ID field, but it contains the ID that WordPress/WooCommerce assign to every post, page, product, order, etc. This number is not shown to the customer. I have customized an order number that is shown to the customer and it’s different from the Woocommerce ID.

How can I get this number into ERPNext, maybe show it next the the Woocommerce ID field? I tried editing the Sales Order doctype by adding a new field. I can edit the label and the type of the field, but the name part is not editable. There is also an options text box, but I’m not sure if I have to enter anything there.