Dynamic XML Datasource in form

[Ian Beaumont <ib...@categoric.com>]

System:Cocoon 2.1.6
 
I'm looking at the form2simpleXML form flow example, and trying to
modify it so that the source document isn't a fixed XML document - but
can be generated from another pipeline (in my case it will come from
eXist - XML DB).
 
First off - I tried to add a generator in to the sitemap (in this
example I'm still using a static doc):
 
     <map:match pattern="form2simpleXML.flow">
       <map:generate src="forms/form2_simple_data.xml"/>
       <map:call function="handleForm">
         <map:parameter name="function" value="form2simpleXML"/>
         <map:parameter name="form-definition"
value="forms/form2_model.xml"/>
         <map:parameter name="documentURI"
value="forms/form2_simple_data.xml"/>
       </map:call>
     </map:match>

but then cannot see how I would change the 
binding_example.js call to:
form.loadXML(documentURI);
to use the document from the pipeline.  It also gives about the
generator already being set when I try to access the page, so I think
this may not me the correct approach.
 
My second solution was to try to use the cocoon protocol as the source
of the xml document - so I changed the sitemap as follows:
     <map:match pattern="test.xml">
       <map:generate src="forms/form2_simple_data.xml"/>
       <map:serialize type="xml"/>
      </map:match>
     
     <map:match pattern="_form2simpleXML.flow">
       <map:call function="handleForm">
         <map:parameter name="function" value="form2simpleXML"/>
         <map:parameter name="form-definition"
value="forms/form2_model.xml"/>
         <map:parameter name="documentURI" value="cocoon:/test.xml"/>
       </map:call>
 
Although this didn't generate any errors - the generated form wasn't
pre-populated from the XML.
 
Help!
 
TIA
Ian