related_backorder_ids causes problem with return picking

[Romain Deheele - Camptocamp]

Hello,

If a picking has a backorder, and we do a return picking (Return Products button on "done" picking)
This next error occurs :
IntegrityError: duplicate key value violates unique constraint "stock_picking_name_uniq"
DETAIL: Key (name, company_id)=(OUT/01014, 1) already exists.
except_osv: ('Constraint Error', 'Reference must be unique per Company!')

To create the incoming picking, the wizard uses a copy method.
This copy includes related_backorder_ids, the previous error occurs when OE tries to create the first related backorder.

Regards,

Romain