Webservice Standard - Import SSingleOrders Lines Product Data

[andrelouca69]

I'm importing the SSingleOrders data to an ERP through the WebserviceStandard and i can´t get the product code in the webservice function "/SSingleOrders/Record/RecordID" to relate the CRM product with the ERP product.
I notice that i can add fields to returned array from webservice by adding custom fields in the SSingleOrders Layout Editor (Main Menu / Standard Modules / Edit Fields / SSingleOrders / Managing Advanced Blocks), but i can't add the "product_code" field to the line.

How can i add the field "product_code" from Products to the response from WebserviceStandard function "/SSingleOrders/Record/RecordID"?

Thanks in advance.