custom field on validation error

I am using Register Plus Redux version 3.9.10. I have added an additional field. It is named account type
Display Radio Fields
Options Youth,Volunteer
database key rpr_account_type

I have show on Registration checked
Required Field checked

On my page in wordpress I provide a link for users to create a new account. The link will go to http://www.mysite.com/wp-login.php?action=register&t=v

The Volunteer account type is checked by default because of the “t=v” get parameter in the link. Everything works fine unless they make a mistake and mistype or forget something.

The form will return telling them where their mistake is. But it does not remember that the Volunteer Option was checked and defaults to the Youth Option. The return link will leave off the “&t=v” get parameter.

ex: http://www.mysite.com/wp-login.php?action=register

I would appreciate any help. Thank you

https://wordpress.org/plugins/register-plus-redux/