Having had a look, the best thing I can come up with is not to record the PO but to 'Save and Preview', and from that window print the copies you need - if you were needing to email, print to PDF. When that is done save as a draft, which does not process the PO, just saves it. When you need to process the PO you will find it in 'Purchases>Open Purchase Order List' and choose 'Draft' from the 'Display Orders' drop-down when you will see all the saved drafts. Open the one you want by double clicking it and then record it in the usual way.
As for the need to input the bill to get the items into inventory. You might try setting up a dummy bank account for this purpose and have a nominal for 'Bill Accruals' and make a payment to that from the dummy bank account. When the bill does arrive, make the necessary journals/ deletions to right the account.
Obviously, this is not an ideal situation, it just adds adds to the process and invites error. Were I NCH I would seriously think about having this program re-written to match current accounting principles, and have it tested by book-keepers and accountants before putting it on the market.