Migration From Asp Site To Cs-Cart


I am planning on migration my 10 year old site written in ASP to CS-Cart. I am trying to minimize loosing google rankings during this migration and maintain same file name structure as on our old site. But, problem is that all files on old site have .asp extension and even if I will re-create same file names structure in CS-Cart, without .asp extension Google will treat these as new web site with new files, and all authority would be lost. Can I have files with .asp extension in CS-cart or how should I proceed so that do not loose Google rankings?

Thanks Eliot

You should find someone who will help you to create 301 redirect rules for you .htaccess file. It should solve your problem