Computed Columns

Hi I didn't find a way to make a computed column out of previous columns defined.

Table LOA_AMT_AmortizationTable{
AMT_LoanID bigint
MonthPeriod int
SaldoInitCapital_PrincipalInitialBalance double
Pago_Payment double
PagoCapital_PrincipalPayment double
PagoInteres_InterestPayment double
PagosCapitalAcumulado_CumulativePrincipalPayments double
PagosInteresesAcumulados_CumulativeInterestPayments double
SaldoFinalCapital_PrincipalEndingPeriodBalance double [cc: SaldoInitCapital_PrincipalInitialBalance - PagoCapital_PrincipalPayment ]
}