Adding new Payment Gateway

I'm planning on developing a new payment gateway where I would want to write the tokenized card number from our cc processing system back to the AuthorizationTransactionCode, would it be best to use the Manual Gateway as a base?

When adding a new Project, what type of project do I need to create?

Thanks.....

Anyone with any suggestion on where I could start?

I would need to grab the CC information, and billing address information to pass to my tokenization service.