Add self issued certificate to iPad

Because iPad will not import self issued certificate same as iPhone does when set up an exchange email account. Therefore I used an alternative way to import certificate.
1. In a PC, open web browser and export the certificate to a file with extension .cer that coding is based 64 encoding. Give a meaningful name, e.g. exchange.cer
2. Send this file to a web mail account, I used gmail.
3. Open the email and tap on the attachment, iPad will pop up a window to install profile that is a certificate of the exchange server, click install, a warning will pop up, ignore it and continue by tap on "Install Now", and exit by tap "Done".
4. Setup exchange email account same as iPhone