New Item Fulfillment

Hi everyone,

I need to add one sales order and after adding sales order then create invoice. And update Order status with "Billed". So i am use the PHPToolkit for this. And add code for adding sales order that is working fine after the inserting sales order then i added the following code for create invoice but it returns an error "The initialize reference type is required.". I f anyone has any idea please help me and also tell me that which parameters could i pass for these functions //$invoiceRecord->clearField( // clear fields created by initialize that cannot be written);