ExportParameters returns Invalid type specified error

Some time ago a customer of mine was trying to export the private key associated to a certificate stored in a smart card, and for that he was trying to use the RSACryptoServiceProvider.ExportParameters method with a code like the following: System.Security.Cryptography.X509Certificates.X509Certificate2 cert = GetCert(certName); RSACryptoServiceProvider rsa = (RSACryptoServiceProvider)