Modifying Unity Pro's Water scripts to just render to an external Render texture?

I hope I'm posting this in the right section, it seemed like more of a scripting issue than shader editing, so here goes!

Basically what I want to do is modify the Pro water script so that it simply renders it's internal Render Textures to external Render Textures instead The thinking behind this is that I want to create my own talior made water shader in Shader Forge and plug the render texture into that instead for my reflections.

I don't have much scripting experience, and have been trawling through the scripts and shaders all day and haven't really got a grasp of where to start.

If anyone can point me in the right direction it would be much appreciated!