Can't login on 3ds

<!-Used an underscore in my pnid, but during login process on the 3ds, the keyboard does not allow for any special characters other than “-” or “.”. Is there any workaround to this, or will i have to make a new pnid?

Underscores are valid characters for usernames. Press either the “symbol” key or “shift” key on the keyboard, the underscore will show