Invoice payment entity

Element	Description	Default	Type	Mandatory
id	Unique id of the payment		INTEGER
invnumber	Invoice number		TEXT
datepaid	Date of payment		DATE	Yes
source			TEXT
memo			TEXT
amount_paid			DOUBLE	Yes
payment_accno		1020	TEXT	Yes
currency		CHF	currency code
exchangerate		1.0	DOUBLE
flag	Possible values are: NEW new payment, EVEN payment has been called by same api-key before, MUTATED payment has changed, DELETED payment has been deleted		TEXT

Examples:

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>

<payments>
  <payment>
    <id>512</id>
    <invnumber>R-001</invnumber>
    <datepaid>2011-11-23T10:39:17.945+01:00</datepaid>
    <amount_paid>570.0</amount_paid>
    <source/>
    <memo>Anzahlung</memo>
    <payment_accno>1020</payment_accno>
    <exchangerate>1.0</exchangerate>
    <flag>NEW</flag>
  </payment>
</payments> 

{
  "id": "512",  
  "invnumber": "R-001",
  "datepaid": "2011-10-24T10:40:24.826+02:00",
  "amount_paid": "570.0",
  "source": "",
  "memo": "Anzahlung",
  "payment_accno": "1020",
  "exchangerate": "1.0"
  "flag": "NEW"
}