Using a sub, sub, webservice with BPA

Hello to all,
I would like to be able to insert a line with BPA in the "Customer" screen, "Sales" tab, "Pricelist per Price Group" sub-tab.

I use this web service: 
main/ifsapplications/projection/v1/CustomerHandling.svc/CustomerInfoSet(CustomerId='CUSTOMER_NAME')/CustOrdCustomers(CustomerId='CUSTOMER_NAME')/CustomerPricelistArray

The problem is that in BPA, I don't see where to add the notion "CustomerPricelistArray" ? : 

This is a request that I have a problem with to set up a customization for one of our customers.
Is it a limitation of the system? 
Thank you.