When using the pyRequestAttachmentPage you will be creating a Multipart request. It is unclear if that's what you are trying to do. If so, you should be using other properties such as pyAttachTypes and pyAttachNames so that the request contains this metadata for the consumer (Service).
If you are just trying to send the plain HTML file, you should be using the mapping settings on the Connector record itself.
The Query String is also configured on the Connector form.