POST api/OpenInvoice

{
  "OpenInvoiceList": {
    "Invoice": [
      {
        "Account": "sample string 1",
        "Amount": "sample string 2",
        "BalDocument": "sample string 3",
        "CC": "sample string 4",
        "Currency": "sample string 5",
        "DocDate": "sample string 6",
        "DocDescription": "sample string 7",
        "DocNumber": "sample string 8",
        "DocType": "sample string 9",
        "ExpDate": "sample string 10",
        "PaymentTerm": "sample string 11",
        "PaymentMethod": "sample string 12",
        "PaymentTermDescription": "sample string 13",
        "RefDate": "sample string 14",
        "RefNumber": "sample string 15",
        "SalesOrg": "sample string 16"
      },
      {
        "Account": "sample string 1",
        "Amount": "sample string 2",
        "BalDocument": "sample string 3",
        "CC": "sample string 4",
        "Currency": "sample string 5",
        "DocDate": "sample string 6",
        "DocDescription": "sample string 7",
        "DocNumber": "sample string 8",
        "DocType": "sample string 9",
        "ExpDate": "sample string 10",
        "PaymentTerm": "sample string 11",
        "PaymentMethod": "sample string 12",
        "PaymentTermDescription": "sample string 13",
        "RefDate": "sample string 14",
        "RefNumber": "sample string 15",
        "SalesOrg": "sample string 16"
      }
    ]
  }
}

<OpenInvoice xmlns:i="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://schemas.datacontract.org/2004/07/WebAPI.Models">
  <OpenInvoiceList>
    <Invoice>
      <OpenInvoiceElements>
        <Account>sample string 1</Account>
        <Amount>sample string 2</Amount>
        <BalDocument>sample string 3</BalDocument>
        <CC>sample string 4</CC>
        <Currency>sample string 5</Currency>
        <DocDate>sample string 6</DocDate>
        <DocDescription>sample string 7</DocDescription>
        <DocNumber>sample string 8</DocNumber>
        <DocType>sample string 9</DocType>
        <ExpDate>sample string 10</ExpDate>
        <PaymentMethod>sample string 12</PaymentMethod>
        <PaymentTerm>sample string 11</PaymentTerm>
        <PaymentTermDescription>sample string 13</PaymentTermDescription>
        <RefDate>sample string 14</RefDate>
        <RefNumber>sample string 15</RefNumber>
        <SalesOrg>sample string 16</SalesOrg>
      </OpenInvoiceElements>
      <OpenInvoiceElements>
        <Account>sample string 1</Account>
        <Amount>sample string 2</Amount>
        <BalDocument>sample string 3</BalDocument>
        <CC>sample string 4</CC>
        <Currency>sample string 5</Currency>
        <DocDate>sample string 6</DocDate>
        <DocDescription>sample string 7</DocDescription>
        <DocNumber>sample string 8</DocNumber>
        <DocType>sample string 9</DocType>
        <ExpDate>sample string 10</ExpDate>
        <PaymentMethod>sample string 12</PaymentMethod>
        <PaymentTerm>sample string 11</PaymentTerm>
        <PaymentTermDescription>sample string 13</PaymentTermDescription>
        <RefDate>sample string 14</RefDate>
        <RefNumber>sample string 15</RefNumber>
        <SalesOrg>sample string 16</SalesOrg>
      </OpenInvoiceElements>
    </Invoice>
  </OpenInvoiceList>
</OpenInvoice>

Sample not available.