Spring MVC Validation for MultipartFile (Complex logic)

I have a task where I'm trying to convert my project from Struts to Spring MVC and running into an issue with MultipartFile where I want to upload multiple attachments and for some reason Spring is not mapping the attachments from the jsp to the component class.

I need an experts help to see what I'm doing wrong.

This should be a very simple task for someone experienced. Budget limited and need this in a day.