I need to insert few rows into OpportunityLineItem table within single POST request https://*.salesforce.com/services/data/v20.0/sobjects/OpportunityLineItem
Single insert works ok for me: {"OpportunityId":"xxx","Quantity":1,"UnitPrice":100,"PricebookEntryId":"xxx"}
But it fails when I try to POST multiple records {"records" : [{"OpportunityId":"xxx","Quantity":1,"UnitPrice":100,"PricebookEntryId":"xxx"}, {"OpportunityId":"xxx","Quantity":4,"UnitPrice":110,"PricebookEntryId":"xxx"}]}