Rome wasn't built in a day!

And you can’t build an supply chain execution system in a day either!

We’ve learned in our implementations of ecVision XpressCommerce that the best way to approach a system rollout is to tackle it in multiple phases. This is especially the case for newer companies that do not have solid processes in place to lead the way through the implementation or companies looking to revamp their processes to better improve efficiency and productivity. Our advice is to always bite off only what you can chew and to take time to step back and look at the system after each phase moves into production and really determine what the next steps should be – what department needs the most help, which reports are executives looking for, where is the focus of the company moving forward? This will help with prioritizing your phased approach in order to reduce the amount of change requests that will cause delays in your rollout.

http://ecvision.com/Products/XpressCommerce.htm