I am having the same issue.  I cant figure out how to customize the express pick pack template and have the changes remain for the next time.  I have no problem to customize the template to make it look how I want, but whether I modify the Intuit template or create a new template, I cant figure out how to have the new template be used when I send an order for express pick/pack and try to print the form.  I dont see that the above explanation helps.