HRESULT STDMETHODCALLTYPE get_Item(
VARIANT VarKey, //the identifier fot the item to return
VARIANT*pvar //a pointer to the item that is returned
);
You can use this method to get the a unique indentifer for items in the ClientCertificates, Cookies, Form, and QueryString collections.
IRequestDictionary, IReadCookie, IWriteCookie IRequest