Form Validation callbacks not passing returned value to next rule

[eluser]september28[/eluser]
Hi there LuckyFella,

The reason is that I am sending data from one server to the other with an api call. I therefore don't want to send the email address unencrypted across the internet. The setup is as follows:

Customer server sends order form to company server which contains order items and customer id and email address. Email address and customer id are encrypted using the api key as a salt.

Company server recieves order and runs validation on post data. Company server first needs to decrypt email and customer id using the api key used to request the url. This all works fine. And as mentioned, my callback function also returns the email address nicely. However the Form_validation library doesn't seem to be passing the decrypted string to the valid_email rule (which is the next rule after the callback), even though I am returning a string from my callback function and not a boolean value.

Hope this makes sense.