can't install SSL certificate in IIs 7

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http://serverfault.com – i tried to install SSL certificate in IIS 7 server (windows server 2008). installation of intermediate certificate in windows mmc console was a success, but when i tried to install the certificate in IIS through server certificates, installation becomes success, but after a refresh installed certificate just vanishes.tried with re keyed certificates and that was not success. as i don't have private keys provided, i was not able to create .pfx files.please help me to sort out this issue.let me know why SSL certificates vanishes in IIS 7 server? (HowTos)