Converting existing voucher number sequence to Month wise number sequence

I have a number sequence that I have selected in journal names as shown bellow (Path : CEU/General ledger/Area page) : 

Now it will generate the voucher number as per the selected number sequence in journal names, but I need to customize the existing number sequence to new that generate the voucher numbers according to the month. The problem I am facing is that where should I add the parameter Fiscal calendar year to the VOUCHER EDT as I am not able to find the Voucher EDT in any module not even in LoadModule method of NumberSeqModuleLedger class. 

I also found the following method that I think defines the scope to the voucher number sequence , if I change it will it change the scope for the voucher number sequence ? , and if yes then please can someone help me out how to change it as I am not even confirmed of the parameter table where I should create the relation with the FiscalCalendar table for the Voucher EDT.

(Method that defines the scope for voucher number) :

public static NumberSeq newGetNumAndVoucherFromCode(
NumberSequenceCode _numberSequenceCode,
NumberSequenceCode _voucherSequenceCode,
NumberSeqScope _scope = NumberSeqScopeFactory::createDefaultScope(),
boolean _voucherMustCopyNum = false,
boolean _makeDecisionLater = false,
boolean _dontThrowOnMissingRefSetUp = false,
//<GEERU><GEEU>
UnknownNoYes _allowManual = UnknownNoYes::Unknown
//</GEERU></GEEU>
)
{
return NumberSeq::newGetNumAndVoucherFromId(
NumberSequenceTable::findByNaturalKey(_numberSequenceCode, _scope.getId()).RecId,
NumberSequenceTable::findByNaturalKey(_voucherSequenceCode, _scope.getId()).RecId,
_voucherMustCopyNum,
_makeDecisionLater,
_dontThrowOnMissingRefSetUp,
//<GEERU><GEEU>
_allowManual);
//</GEERU></GEEU>
}