RSA Sign with PHP, verify with C#

Question

Unfortunately I haven't found anything that works for me yet so I'll create a new question.
My PHP Code (using phpseclib's RSA) that signs the string, as you might notice the code is to verify a license code.

<?php
include('Crypt/RSA.php');

$rsa = new Crypt_RSA();
//$rsa->setPassword('password');
$rsa->loadKey('-----BEGIN RSA PRIVATE KEY-----
...
-----END RSA PRIVATE KEY-----
'); // private key

$plaintext = 'AAAAA-AAAAA-AAAAA-AAAAA';

$rsa->setSignatureMode(CRYPT_RSA_SIGNATURE_PKCS1);
$signature = $rsa->sign($plaintext);
echo base64_encode($signature);

The C# code that should verify the response:

            bool success = false;
            using (var rsa = new RSACryptoServiceProvider())
            {
                StreamReader reader = new StreamReader(dataStream);
                String signedString = reader.ReadToEnd();
                byte[] signedBytes = Convert.FromBase64String(signedString);
                byte[] bytesToVerify = Encoding.UTF8.GetBytes(value);
                try
                {
                    RSAParameters parameters = new RSAParameters();
                    parameters.Exponent = new byte[] { 0x01, 0x10, 0x01 };
                    parameters.Modulus = OtherClass.StringToByteArray(Program.Modulus);
                    rsa.ImportParameters(parameters);

                    success = rsa.VerifyData(bytesToVerify, new SHA1CryptoServiceProvider(), signedBytes);
                }
                catch (CryptographicException e)
                {
                    Console.WriteLine(e.Message);
                }
                finally
                {
                    rsa.PersistKeyInCsp = false;
                }
            }

dataStream is the webrequest's response stream.

Answer 1

I've solved this now by using another way to load the key.
I've used this online converter to convert my PEM key to a XML key: https://superdry.apphb.com/tools/online-rsa-key-converter

So I changed the try { ... } part to:

rsa.FromXmlString("{XML_KEY}");
success = rsa.VerifyData(bytesToVerify, new SHA1CryptoServiceProvider(), signedBytes);

Now it works just fine. I guess I didn't really understand how to load a key via modulus and exponent.