instalmentDetails applies if the cart is to be paid for in instalments.
| Field ID | Description | Type | Occurrence |
| installmentFrequencyType | Installment frequency type | String | 1..1 |
| installmentFrequencyDescription | Installment frequency description | String | 1..1 |
| numberOfInstallments | Number of installments | Integer | 1..1 |
| installmentStartDate | Installment start date | Date | 1..1 |
| installmentEndDate | Installment end date | Date | 1..1 |
| minimumRepaymentAmount | Minimum repayment amount | Decimal | 1..1 |
| totalInstallmentAmount | Total installment amount | Decimal | 1..1 |
