Business process, file param type

Hi,

is there any documentation on how to use the File param type in a business process? I wasn't able to find any.

I have a use case where i have to save a file as an attachment to an entity, starting from a base64 rappresentation of the file. I would like to accomplish this task with the least amount of coding. What i envisioned is a business process with a script task that converts the base64 to a File param. Then a process file shape that saves the File param. Sadly i'm dead in the water on how to implement this scenario because i have no idea on how to use File param type. I can't even understand what .Net/Terrasoft type it is. Do you have any suggestion?