About FacetChart creating

I want to show a facetchart in a window component with xml file.the file as follow:
<FacetChart ID="simpleChart" autoDraw="false" dataSource="PssPurchaseCompare2">
<valueProperty>sales</valueProperty>
<data>
<CellRecord>
<region>Jan</region>
<product></product>
<sales></sales>
</CellRecord>
<CellRecord>
<region>Feb</region>
<product></product>
<sales>20</sales>
</CellRecord>
</data>
<facets>
<Facet>
<id>region</id>
<title>Region</title>
</Facet>

<Facet>
<id>product</id>
<title>Product</title>
</Facet>
</facets>
</FacetChart>
abour that, the data is static.Now，I want to show datas from a listGrid and the listGrid has contained datas.the queation is I do not know how to transport the datas to the faceschart in xml file.who can help me!!!