Read this for emote pack

//Messenger Content Installer Type Library
//Version: 1.0
MessengerContentInstallerLibrary;
GUID = {C1637F37-3FC8-4B37-B3B2-6CC5E202390D};


Dispatch DMessengerContentEvents;
GUID = {51A01E38-7505-401B-ABC9-F460E1499728};
  function OnContentInstalled(lhrResult: I4); stdcall;

//Single Click Download Interface
Dispatch IMessengerContent;
GUID = {83B2A407-22B9-4842-97C6-DE30EC6DAC3E};
  function QueryInterface(riid: ^GUID; out ppvObj: ^^VOID); stdcall;
  function AddRef: UI4; stdcall;
  function Release: UI4; stdcall;
  function GetTypeInfoCount(out pctinfo: ^UINT); stdcall;
  function GetTypeInfo(itinfo: UINT; lcid: UI4; out pptinfo: ^^VOID); stdcall;
  function GetIDsOfNames(riid: ^GUID; rgszNames: ^^I1; cNames: UINT; lcid: UI4; out rgdispid: ^I4); stdcall;
  function Invoke(dispidMember: I4; riid: ^GUID; lcid: UI4; wFlags: UI2; pdispparams: ^DISPPARAMS; out pvarResult: ^Variant; out pexcepinfo: ^EXCEPINFO; out puArgErr: ^UINT); stdcall;
  //Download content to the client from a CAB file.
  function InstallContent(bstrURL: BSTR); stdcall;
  //Download content to the client from a Merchant CAB file.
  function InstallIndirectContent(bstrURL: BSTR); stdcall;

//Single Click Download Interface v2
Dispatch IMessengerContent2;
GUID = {647C4DDA-B572-4EEF-871A-7ED254E680F7};
  function QueryInterface(riid: ^GUID; out ppvObj: ^^VOID); stdcall;
  function AddRef: UI4; stdcall;
  function Release: UI4; stdcall;
  function GetTypeInfoCount(out pctinfo: ^UINT); stdcall;
  function GetTypeInfo(itinfo: UINT; lcid: UI4; out pptinfo: ^^VOID); stdcall;
  function GetIDsOfNames(riid: ^GUID; rgszNames: ^^I1; cNames: UINT; lcid: UI4; out rgdispid: ^I4); stdcall;
  function Invoke(dispidMember: I4; riid: ^GUID; lcid: UI4; wFlags: UI2; pdispparams: ^DISPPARAMS; out pvarResult: ^Variant; out pexcepinfo: ^EXCEPINFO; out puArgErr: ^UINT); stdcall;
  //Download content to the client from a CAB file.
  function InstallContent(bstrURL: BSTR); stdcall;
  //Download content to the client from a Merchant CAB file.
  function InstallIndirectContent(bstrURL: BSTR); stdcall;
  //Messenger version
  property-get Version: BSTR; stdcall;

//Single Click Download Interface v3
Dispatch IMessengerContent3;
GUID = {DE72ACCE-9D1D-4484-8A5E-5C5B517153CC};
  function QueryInterface(riid: ^GUID; out ppvObj: ^^VOID); stdcall;
  function AddRef: UI4; stdcall;
  function Release: UI4; stdcall;
  function GetTypeInfoCount(out pctinfo: ^UINT); stdcall;
  function GetTypeInfo(itinfo: UINT; lcid: UI4; out pptinfo: ^^VOID); stdcall;
  function GetIDsOfNames(riid: ^GUID; rgszNames: ^^I1; cNames: UINT; lcid: UI4; out rgdispid: ^I4); stdcall;
  function Invoke(dispidMember: I4; riid: ^GUID; lcid: UI4; wFlags: UI2; pdispparams: ^DISPPARAMS; out pvarResult: ^Variant; out pexcepinfo: ^EXCEPINFO; out puArgErr: ^UINT); stdcall;
  //Download content to the client from a CAB file.
  function InstallContent(bstrURL: BSTR); stdcall;
  //Download content to the client from a Merchant CAB file.
  function InstallIndirectContent(bstrURL: BSTR); stdcall;
  //Messenger version
  property-get Version: BSTR; stdcall;
  //Install content to the client from XML data.
  function InstallMobileContent(bstrXML: BSTR); stdcall;

//Messenger Content Installer Object
CoClass MessengerContentInstaller;
GUID = {F06608C7-1874-4EEA-B3B2-DF99EBB144B8};

//This is not real code, it's for understanding only.
void DoInstallContent(char * szPathToCabToInstall)
{
    IMessengerContentPtr pMsgrContent;
    pMsgrContent.CreateInstance(); // How this works depends on your language.  For C or C++, you would use CoCreateInstance or the InterfacePtr wrappers

    // Verify object was created successfully. (not shown)

    UINT nRandomPortNumber = GenerateRandomUnusedPortNumber();

    MiniHttpServer server(nRandomPortNumber, szPathToCabToInstall);

    HRESULT hr = pMsgrContent->InstallContent("http://localhost:"+nRandomPortNumber+"/AnyNameWillDo.cab");

    // Ensure the function succeeded, if not display some sort of error message. (not shown)
}

void MiniHttpServer::OnIncommingConnection()
{
    Socket sock;
    Accept(sock);  // Accept the incomming connection

    if (FileDoesNotExist(szPathToCabToInstall))
    {
        sock.Send("HTTP/1.1 404 NOT FOUND\r\n");
        sock.Close();
        // In Theory, this code should never be run because you should have given it a valid file name.
    }

    String szDataToSend = "HTTP/1.1 404 NOT FOUND\r\n";
    szDataToSend+="Date: Thu, 09 Jun 2005 02:40:56 GMT\r\n"; // Any date is fine. This happens to be when I wrote the code. :P
    szDataToSend+="Server: Apache/1.3.33 (Unix) mod_jk/1.2.6-dev PHP/5.0.4 mod_ssl/2.8.22 OpenSSL/0.9.7g\r\n"; // You can put any desired server signature here.
    szDataToSend+="Content-Length: "+FileLength(szPathToCabToInstall)+"\r\n";  // Length of the data to be sent
    szDataToSend+="Keep-A****** timeout=15, max=100\r\n"; 
    szDataToSend+="Connection: Keep-Alive\r\n"; // Now why did I have this as Keep-Alive? I don't rememeber. Perhaps it can be "Connection: close" since we are closing the socket afterwards anyways.
    szDataToSend+="Content-Type: text/plain\r\n"; // technically this isn't true, but it works, so we don't care
    szDataToSend+="\r\n";

    sock.BufferSendData();  // Not really a function, but we want to send the headers and the data at the same time so we pretend to buffer the data.
    sock.Send(szDataToSend);
    sock.Send(GetFileData(szPathToCabToInstall));
    sock.FlushSendBuffer();

    sock.Close();   // Close the accepted client socket.
    this->Close();  // Close the server socket as we don't need it anymore
}