Global form validation callbacks? Staged forms?

[eluser]tomclowes[/eluser]
Further to this, re point 2.

I have created the MY_Form_validation class, defined the function capcha check and utilized the CI superglobal.

I have changed the rules required in my Form_validation config file from 'callback_capcha_check' to simply 'capcha_check'.

None of my form validation functions are working - not even the default CI ones..

Thanks