milobloom -- V5 supports text file attachments which would allow you to create and customize your own text file packing lists -- this does take a little work on your part as you would have to design the text file attachment whereas the PDF packing list is pre-designed and unchangeable.

PO_FROM_EMAIL_NAME is an option you define in Admin->Configuration->Purchase Orders. You need to setup all the options here as well. It does strike me as odd though that you have PO_FROM_EMAIL_NAME....this is the what the value you set up in Zen Cart Admin is defined as. Are you sure you ran the SQL patch? If you did, you will find Purchase Orders under Admin->Configuration.

The PDF will include your address if you set it up with Zen Cart. Check your Contact Us page -- the same information will be on the purchase order. You can set this up under Admin->Configuration->My Store->Store Address and Phone.