Get certificate for USB Token (eToken, iKey1000)

Dear,
I am developing an application to be signed XML documents, one way is through signing the repository of digital certificates for Windows.
But also must be able to sign the certificates that are in a USB token and my question is:
How can I get certificates that are in the USB token, for example, eToken, iKey1000

I am using this code.

SecureString oSecurePass = new SecureString ();
             oSecurePass.AppendChar ( 'a');
             oSecurePass.AppendChar ( 'b');
             oSecurePass.AppendChar ( 'c');
             oSecurePass.AppendChar ('1 ');
             oSecurePass.AppendChar ('2 ');
             oSecurePass.AppendChar ('3 ');
             CspParameters csp = new CspParameters (1, "eToken Base Cryptographic Provider");
             csp.KeyPassword = oSecurePass;
             csp.Flags = CspProviderFlags.UseDefaultKeyContainer;
             RSACryptoServiceProvider rsa = new RSACryptoServiceProvider (csp);


rsa.CspKeyContainerInfo.UniqueKeyContainerName property and get the name, but I can not remove the digital certificate, also if there is more than one certificate only shows me one of them.

Thank you very much for your help.