Install certifcates with IE7

when i have installed Windows Vista i have a problem to install a
certificate with Internet explorer.
I succeed to demand and to install ( at CA ) a certificate. but then when i
am connected to the web site, not there certifcates to introduce. If demand
ena install a certifcate with firefox not there are problems.
I have found this link who is my
problem, but following step by step the guide i have the same problem.
My UAC is disabled.