Multidimensional Flashdata arrays?

[eluser]sacarias[/eluser]
Well, say if i want to sign up to a website. With the current form validation class - on success, you would have to make a success page. I dont want to do that.
I would like to have the user stay on the same page that they signed up on and they would see a success message. EX.(Thanks for signing up, please check your email to validate your account before you log in.);