Service output templates

Basically, Trading partner send xml, my TN receives the xml, assigns a doctype, call a processing rule, which calls a flow service, the flow service modifies the incoming xml from TN and outputs HTML, that HTML is then sent back the trading partner via TN. Can I accomplish this with a service output template, or do I need to look into alternative implementations?

I have implemented a small proof of concept, whereby I http post an xml file to TN and via doctype/processing rule, I execute my flow service. The flow service uses a service output template to create HTML. I have tested this through the developer, by selecting Run in Browser and it works. But now I want to take JUST the HTML and send it back to the trading partner using TN, ie, recordToBizDoc, routeBizDoc, only problem is the HTML that the service output template created is not on the pipeline, so only the xml is being return to the trading partner instead of the HTML.