How to? Two web forms edit the same xml

[parrym]

I have created two web forms one called portal and one called category. A portal can contain 0 to unbounded categories and displays them as links. A category has to select 1 portal to which it belongs. Portal generates (for example) portal_1.xml. However if I now create a new category category_1.xml I want it to update whichever portal is selected in this case portal_1.xml however I am having trouble renditioning a file originally created with the portal web form using the category web form.

Is there a way to bypass this error:

Error generating rendition using category_portal.xsl: node avm://resource-center2–admin–preview/-1;www;avm_webapps;ROOT;portals;portal_1.xml does not have aspect {http://www.alfresco.org/model/wcmappmodel/1.0}rendition
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I have tried editing RenditionImpl and commenting out

throw new IllegalArgumentException("node " + nodeRef + " does it it it not have aspect " + WCMAppModel.ASPECT_RENDITION);
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but that didn't help and produced another error:

javax.faces.FacesException: javax.el.PropertyNotFoundException: Property 'labelAttribute' not found on type org.alfresco.web.forms.RenditionImpl
caused by:
org.apache.jasper.JasperException: javax.el.PropertyNotFoundException: Property 'labelAttribute' not found on type org.alfresco.web.forms.RenditionImpl
caused by:
javax.el.PropertyNotFoundException: Property 'labelAttribute' not found on type org.alfresco.web.forms.RenditionImpl
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I appreciate any help people may have to offer.

Is there a better way of updating an existing xml file on the creation of another through a web form (without requiring the published html to be dynamic)?

[parrym]

I'm not sure if I was very clear on what I am trying to achieve, above. Basically I want to be able to update an existing XML document created by web form 1 using web form 2. Any help would be greatly appreciated.