[Users] mapfish print/ geoext print.provider issue

[Brad Bordine]

I am trying to make a Ext grid object print out via mapfish print and am
unclear how to send the "grids" parameter through the spec. There is an
example of a user sending the grids parameter to the Mapfish "print
widget (http://web.archiveorange.com/archive/v/0qLmXVvRWkxmMKrmM5kL)
however no one mentions how to do that using the print.provider GeoExt
widget, which seems to be the object communicating with the server
Mapfish widget. We are aware of the need for configuring the YAML but at
the moment are trying to figure out how to get the right spec. Relevant
snippets are below

        avoidedgrid = new Ext.grid.GridPanel({
             title: "Total Avoided Costs for 1MW at Specified Location",
             id: 'gridpanel',
             renderTo: "gridoutput",
             height:75,
             width:365,
             collapsible: true,
             iconCls: 'icon-grid',
             ds: ds,
             cm: colModel
         });

var printProvider = new GeoExt.data.PrintProvider({
         method: "POST", // "POST" recommended for production use
         layout: ('Letter'),
         capabilities: printCapabilities, // from the info.json script
in the html
         customParams: {
             mapTitle: "DECA Map",
             dpi: 300,
             grids: [avoidedgrid]
         }
     });