How does one change the setting on pastel express 2009 if you process a payment in the cashbook on the customers side (receipts) to show on the statement as a lump sum and not link it individually on the invoices?

It's always been like this, and this morning after I've done the cash book, suddenly it has changed to linking separate. I would like to change it back to show the lumps sum paid. Can someone please help me??