Cant find it!

I am looking for and cant find the EncryptPassword function from System.Web.Security.Membershipprovider.  Am I missing something here, I have been attempting to integrate YAF into my site and am almost there, I just need to find this last function.  Below is the line that I need to use, I just need to find EncryptPassword() and add it to my page.

 return Convert.ToBase64String((new YafMembershipProvider()).EncryptPassword(buffer));
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