S/MIME certificate removed but Mail still encrypting messages

Hi,
I'm using Mail to send S/MIME encrypted messages. I imported someone's X.509 Certificate in my iPhone so that Mail uses it for encryption. Now I want to remove this certificate. I went to

Settings > General > Profiles > Configuration Profiles

and deleted the certificate from there.

Now if I open Mail and start composing an email to the contact, Mail still uses the certificate to encrypt which I do not want anymore. Where is Mail getting the certificate from ? How can I really remove it ?

cheers
Tex

FYI, I wrote an article about it

http://securitylearn.wordpress.com/2012/06/30/ios-5-smime-profile-deletion-bug/