This will create a new Invoice and optionally send it to a Contact

This will create a new Invoice and optionally send it to a Contact. Please note that this request requires valid parameters for all associated members of the Invoice or the request will fail. If you have doubled-checked all parameters and the request is still failing, check that the payload JSON format is correct by using <a href="http://jsonlint.com/">JSONLint</a>. If credit card and billing information already exist for this contact, you may omit <b>billing_address</b> and <b>payer</b> from the request. Note that <b>trans_date</b> is given in milliseconds elapsed since midnight on 1/1/1970.