account button buy callback carts com digitally important integration method settings shopping signed site unaffected url xml

I HAVE A QUESTION ABOUT XML DIGITALLY SIGNED SHOPPING CARTS. I am trying to use the BUY IT NOW BUTTON ON ANOTHER SITE and it is saying that I need to change my integration settings. How important is this. If I change this, will it affect my account with e-junkie.com

The only important settings are the callback URL and Callback method (XML). As long as you don't change those, E-junkie will stay unaffected.