Add a list in a report using a job

Hi,

I'm a beginner with developing SSRS reports and I have this little issue: I have to add a list of items in a report header and I dont't know how to proceed. 

I developed a job that allows me to list the PackingSleepIds based on the RecId of the costumer order and I need to bring this list on the header of the SalesInvoice report (for any costumer order of course).

This is my job:

static void InvoicePackingSlip(Args _args)
{
InventTrans inventTrans;
InventTransOrigin inventTransOrigin;
CustInvoiceTrans custInvoiceTrans;
CustInvoiceJour custInvoiceJour;
str packingSlip;
;

custInvoiceJour = custInvoiceJour::findRecId(5637157350);

while select inventTrans group by PackingSlipId join inventTransOrigin join custInvoiceTrans
where inventTrans.InventTransOrigin == inventTransOrigin.RecId &&
inventTransOrigin.InventTransId == custInvoiceTrans.InventTransId &&
custInvoiceTrans.SalesId == custInvoiceJour.SalesId &&
custInvoiceTrans.InvoiceId == custInvoiceJour.InvoiceId &&
custInvoiceTrans.InvoiceDate == custInvoiceJour.InvoiceDate &&
custInvoiceTrans.numberSequenceGroup == custInvoiceJour.numberSequenceGroup
{
packingSlip = packingSlip + inventTrans.PackingSlipId +", ";
}

info(packingSlip);

}