Doco for Using Security says use this:
<application> <view-handler>org.jboss.seam.ui.facelet.SeamFaceletViewHandler</view-handler> </application>
<application> <view-handler>com.icesoft.faces.facelets.D2DSeamFaceletViewHandler</view-handler> </application>
I believe the only thing the Seam ViewHandler does is include the enhanced EL capabilities. My understanding is that the recent versions of icefaces do this too, so you should be ok with it.