Embedding existing page in a CakePHP site

We have an existing PHP page (from an earlier project) which could be described as cryptic and ancient. It basically displays a form, catches the input and runs an external application to process the input and then pipes the output to the user.

I would really like not to modify this file any more than is required. Would there be an easy way to just make this file magically work by copying it to some location in the CakePHP's directory and have it receive $POST etc. as usual?