I followed this doc (http://doc.silverstripe.org/sapphire/en/reference/dataobject) and tried to show Payment Amount in the summary table but failed. Here is my change to Payment.php
public static $summary_fields = array(
'ID' => 'ID',
'Status' => 'Status',
'Amount.amount' => 'aaa',
'Message' => 'Message'
PaymentDate and Message show correctly but an empty column for 'aaa' above in the summary table.
'Amount.getAmount', 'Amount.getAmount()', 'Amount.Amount' give no difference.
Any advice is appreciated