problem in Payment gateway

[Alok yadav]

i am using the link of metacharge.com for payment gateway, when i post data
throung IE it give the correct response, but when i use the .net code to post
data the response is not correct.message is some data is missing.
i use the following code:

public class httpClass
{

private string UserName;
private string UserPwd;
private string ProxyServer;
private int ProxyPort;
private string Request;

public httpClass(strin g HttpUserName,
string HttpUserPwd, string HttpProxyServer ,
int HttpProxyPort, string HttpRequest)
{
UserName = HttpUserName;
UserPwd = HttpUserPwd;
ProxyServer = HttpProxyServer ;
ProxyPort = HttpProxyPort;
Request = HttpRequest;
}

/// <summary>
/// This method creates secure/non secure web
/// request based on the parameters passed.
/// </summary>
/// <param name="uri"></param>
/// <param name="collHeade r">This parameter of type
/// NameValueCollec tion may contain any extra header
/// elements to be included in this request </param>
/// <param name="RequestMe thod">Value can POST OR GET</param>
/// <param name="NwCred">I n case of secure request this would be
true</param>
/// <returns></returns>
public virtual HttpWebRequest CreateWebReques t(string uri,
NameValueCollec tion collHeader,
string RequestMethod, bool NwCred)
{
HttpWebRequest webrequest =
(HttpWebRequest ) WebRequest.Crea te(uri);
webrequest.Keep Alive = false;
webrequest.Meth od = RequestMethod;

int iCount = collHeader.Coun t;
string key;
string keyvalue;

for (int i=0; i < iCount; i++)
{
key = collHeader.Keys[i];
keyvalue = collHeader[i];
webrequest.Head ers.Add(key, keyvalue);
}

webrequest.Cont entType = "text/html";
//"applicatio n/x-www-form-urlencoded";

if (ProxyServer.Le ngth 0)
{
webrequest.Prox y = new
WebProxy(ProxyS erver,ProxyPort );
}
webrequest.Allo wAutoRedirect = false;

if (NwCred)
{
CredentialCache wrCache =
new CredentialCache ();
wrCache.Add(new Uri(uri),"Basic ",
new NetworkCredenti al(UserName,Use rPwd));
webrequest.Cred entials = wrCache;
}
//Remove collection elements
collHeader.Clea r();
return webrequest;
}//End of secure CreateWebReques t

/// <summary>
/// This method retreives redirected URL from
/// response header and also passes back
/// any cookie (if there is any)
/// </summary>
/// <param name="webrespon se"></param>
/// <param name="Cookie"></param>
/// <returns></returns>
public virtual string GetRedirectURL( HttpWebResponse
webresponse, ref string Cookie)
{
string uri="";

WebHeaderCollec tion headers = webresponse.Hea ders;

if ((webresponse.S tatusCode == HttpStatusCode. Found) ||
(webresponse.St atusCode == HttpStatusCode. Redirect) ||
(webresponse.St atusCode == HttpStatusCode. Moved) ||
(webresponse.St atusCode == HttpStatusCode. MovedPermanentl y))
{
// Get redirected uri
uri = headers["Location"] ;
uri = uri.Trim();
}

//Check for any cookies
if (headers["Set-Cookie"] != null)
{
Cookie = headers["Set-Cookie"];
}
// string StartURI = "http:/";
// if (uri.Length 0 && uri.StartsWith( StartURI)==fals e)
// {
// uri = StartURI + uri;
// }
return uri;
}//End of GetRedirectURL method
public virtual string GetFinalRespons e(string ReUri,
string Cookie, string RequestMethod, bool NwCred)
{
NameValueCollec tion collHeader =
new NameValueCollec tion();

if (Cookie.Length 0)
{
collHeader.Add( "Cookie",Cookie );
}

HttpWebRequest webrequest =
CreateWebReques t(ReUri,collHea der,
RequestMethod, NwCred);

BuildReqStream( ref webrequest);

HttpWebResponse webresponse;

webresponse = (HttpWebRespons e)webrequest.Ge tResponse();

Encoding enc = System.Text.Enc oding.GetEncodi ng(1252);
StreamReader loResponseStrea m = new
StreamReader(we bresponse.GetRe sponseStream(), enc);

string Response = loResponseStrea m.ReadToEnd();

loResponseStrea m.Close();
webresponse.Clo se();
return Response;
}

private void BuildReqStream( ref HttpWebRequest webrequest)
//This method build the request stream for WebRequest
{
Stream oStreamOut= webrequest.GetR equestStream();
byte[] byteArray = Encoding.UTF8.G etBytes(Request );
oStreamOut.Writ e(byteArray,0,R equest.Length);
oStreamOut.Clos e();

}
}
}//End of HttpBaseClass class
please help me.