[sukhanchik]

public void myMethod(LedgerBalances _ledgerBalances, AmountMST _amountDebitMST)
{
    LedgerBalancesDimTrans ledgerBalancesDimTrans;
;
    if (_ledgerbalances.TableId == tablenum(LedgerBalancesDimTrans))
    {
        ledgerBalancesDimTrans = _ledgerBalances;
        ledgerBalancesDimTrans.DebitMSTTest += _amountDebitMST; // Поле amountDebitMST должно существовать в таблице LedgerBalancesDimTrans 
    }
}