Clustering GeoRSS layer

Using Flexviewer 3.4 I try to set clustering for GeoRSS layer. I copied the code from
http://resources.arcgis.com/en/help/...0000004z000000
However, I did not succeed to get clustering to work for GeoRSS layer.

<layer label="UN-ASIGN GeoRSS"
type="georss"
visible="true"
url="http://asign.cern.ch/resources/georss/crowd_photo.xml">
<clustering mingraphiccount="1" sizeinpixels="80">
<clustersymbol type="flare"
alphas="0.2,0.7,1"
colors="0xFFFF00,0xFFA500,0xFF0000"
flaremaxcount = "10"
size="30"
sizes = "30,60,90"
textsize="14"
textcolor="0x000000"
bordercolor="0xb28f00"
weights="10,100,9999"/>
</clustering>
</layer>

In addition, I would also like to know if it is possible to change symbol for GeoRSS layers.

Thanks for any support and ideas.

Ivan Baehr
UNOSAT