test.p12 is attached. Use IE to import the certificate/private key into the browser's keystore. Password is "test". Then run the following:

    public static void main(String[] arg) throws Exception {
        PrivateKey privKey = null;
        Certificate cert = null;
        KeyStore ks = KeyStore.getInstance("Windows-MY");
        ks.load(null, null);
        PublicKey myPuKey = (PublicKey)
            ks.getCertificate("test_cert0").getPublicKey();

        Cipher rsa = Cipher.getInstance("RSA/ECB/PKCS1Padding", "SunMSCAPI");
        rsa.init(Cipher.ENCRYPT_MODE, myPuKey);

myPuKey is a sun.security.rsa.RSAPublicKeyImpl here.

But MSCAPI checks that:

        if (!(key instanceof sun.security.mscapi.Key)) {
            throw new InvalidKeyException("Unsupported key type: " + key);
        }

The current MSCAPI will choke on this in two places with an Unsupported key type. First in engineGetKeySize, and then in the actual Cipher's init routine.