Voucher not specified as of … Dynamics Ax 2012 R3

A year ago, I did some customization, where ledger entries are done with X++ code. Now client wants Reverse ledger entries. As per logic reverse ledger entries has only difference is debit amount will be credit amount and versa vise. With X++ code  80 percent of these entries are successful, But 20 percent were fail with following Error.

Voucher not Specified as of …

So what is solution. I found only solution to read next voucher from sequence number and assign to ledger trans before posting it. I used following code snippet to get and set next voucher

    select firstOnly numSeqTable

where numSeqTable.RecId  == ledgerJournalName.NumberSequenceTable;

if (numSeqTable)

{

numberseq = numberseq::newGetVoucherFromCode(numSeqTable.NumberSequence);

trans.parmVoucher( numberseq.voucher());

}

Now customization works perfectly fine.