Is WebProxy class only support HTTP proxy type?

Is there a way to use Socks4, Socks4a or Socks5 proxy types with WebProxy class. I have downloaded a Proxy Server "ccproxy" from http://www.youngzsoft.net/ccproxy/screenshot.htm where i can use my code to download and upload files but it works only with Port 808 reserved for HTTP proxy in ccproxy server.

Http Get Code...

WebClient client = new WebClient();
if (tbpassword.Text != "" && tbUsername.Text != "") 
{ 
 NetworkCredential auth = new NetworkCredential(tbUsername.Text, tbpassword.Text);  
 client.Credentials = auth; 
} 
if (tbProxyAddress.Text != "" && tbProxyPort.Text != "") 
{ 
WebProxy proxy = new WebProxy(tbProxyAddress.Text,Convert.ToInt32(tbProxyPort.Text)); 
 if(tbProxyUsr.Text != "" && tbProxyPwd.Text != "") 
 proxy.Credentials = new NetworkCredential(tbProxyUsr.Text, tbProxyPwd.Text); 
client.Proxy = proxy; 
} 
Uri uri = new Uri(tbURL.Text); 
client.DownloadFile(uri, tblocalFile.Text); client.Dispose(); 

HTTP Post Code...
 
WebClient client = new WebClient(); 

if (tbpassword.Text != "" && tbUsername.Text != "") 
{ 
NetworkCredential auth = new NetworkCredential(tbUsername.Text, tbpassword.Text); client.Credentials = auth;
} 
if (tbProxyAddress.Text != "" && tbProxyPort.Text != "") 
{ 
 WebProxy proxy = new WebProxy(tbProxyAddress.Text, Convert.ToInt32(tbProxyPort.Text)); 
 if (tbProxyUsr.Text != "" && tbProxyPwd.Text != "") 
 proxy.Credentials = new NetworkCredential(tbProxyUsr.Text, tbProxyPwd.Text);
 client.Proxy = proxy; 
} 
Uri uri = new Uri(tbURL.Text); 
System.Collections.Specialized.NameValueCollection collect = new System.Collections.Specialized.NameValueCollection(); 
collect.Add("input", "Ronak"); 
collect.Add("submit", "Submit"); 
byte[] btArray = client.UploadValues(uri, "POST", collect); 
//byte[] btArray = client.UploadFile(uri, "POST", tblocalFile.Text); MessageBox.Show(Encoding.UTF8.GetString(btArray)); client.Dispose();