Oh, dear. Please do not use brainwallets! Brainwallets are insecure. AVOID.
I call brainwallets wallets for the brainless; but you neednt take my word for it:
Unless I'm missing something the brain wallet you're referring are places where people try to remember the seed of the wallet and not Brainwalletx which is just a site with a bunch of tools including verify signed messages (and ofc generating brain wallet seeds)