nokia 6600 firmware problem!!

Hi All

I have a following strange problem with Nokia 6600
I have this code for sending of data to server via HTTP EPOST method. I use RHttpTransaction for submit of data.

_LIT8(KContentType, "text/html");


RStringPool string_pool = iHttpSession.StringPool();
RStringF method = string_pool.StringF(HTTP::EPOST, RHTTPSession::GetTable());
   
TUriParser8 uri;
uri.Parse(*request);   

iTransaction = iHttpSession.OpenTransactionL(uri, *this, method);
   
RHTTPHeaders hdr = iTransaction.Request().GetHeaderCollection();
   
RStringF cont_type_str = string_pool.OpenFStringL(KContentType);
THTTPHdrVal cont_type(cont_type_str);
hdr.SetFieldL(string_pool.StringF(HTTP::EContentType,RHTTPSession::GetTable()), cont_type);
cont_type_str.Close();   

iTransaction.Request().SetBody(*this);
iTransaction.SubmitL();

This code work perfect on mobile with firmware ver 5.27!
But on mobile with lower firmware for example 4.09 it don't work - In my MHFRunL function i recieve aEvent.iStatus = -5 ("The operation requested is not supported")

Any solution on this problem??

thanks !