如何将已编写的CodeIgniter代码移至Kohana？

I've been using CodeIgniter for some time, and I liked it a lot. It looks like I need to move to Kohana though, because my other team member needs our code to fully use PHP5 features to their fullest extent. The problem is we have already coded over half of our project in CodeIgniter. Has anyone transferred code from CodeIgniter to Kohana before? Is it even possible to do, and how much effort will it take if so? Thank you in advance!I've been using CodeIgniter for some time, and