Newbie question: Web service for uploading files using soap

[Aniruddha Shevade <as...@actuate.com>]

Hello
  I am writing a C++ soap server. I want to  add a service which will enable
the end user to upload a file.
I beleive this can be done using soap attachments. The problem is that if
the file size if not known, then mostly 
we have to use something like a HTTP chunked protocol. Is there any place
where I can find refernce / sample code for 
such a case. Even if the file size is known , where does it have to be
specified ( in the HTTP header I guess ) ?
Any help is appreciated

thanks
-Aniruddha