similar to following code in view_receipt.php
display_allocations_from(PT_CUSTOMER, $receipt['debtor_no'], ST_CUSTPAYMENT, $trans_id, $receipt['Total']);
we can add
display_allocations_to(PT_CUSTOMER, $receipt['debtor_no'], ST_SALESINVOICE, $trans_id, $receipt['Total']);
custalloc_db.inc has function get_allocatable_to_cust_transactions similarly we can write function get_allocatable_FROM_cust_transactions
as below -
function get_allocatable_from_cust_transactions($customer_id, $trans_no=null, $type=null)
{
if ($trans_no != null and $type != null)
{
$sql = get_alloc_trans_sql("amt", "trans.trans_no = alloc.trans_no_from
AND trans.type = alloc.trans_type_from
AND alloc.trans_no_to=".db_escape($trans_no)."
AND alloc.trans_type_to=".db_escape($type)."
AND trans.debtor_no=".db_escape($customer_id),
"".TB_PREF."cust_allocations as alloc");
}
else
{
$sql = get_alloc_trans_sql(null, "round(ov_amount+ov_gst+ov_freight+ov_freight_tax+ov_discount-alloc,6) > 0
AND trans.type <> " . ST_CUSTPAYMENT . "
AND trans.type <> " . ST_BANKDEPOSIT . "
AND trans.type <> " . ST_CUSTCREDIT . "
AND trans.type <> " . ST_CUSTDELIVERY . "
AND trans.debtor_no=".db_escape($customer_id));
}
return db_query($sql." ORDER BY trans_no", "Cannot retreive alloc to transactions");
}
Hope I am clear enough. 
Thanks
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