This will not come up until 2009 returns are filed i.e. September 2009 is the first payment date. So there's time for this to be clarified, however it was recently suggested that as it is a tax it is not deductible for tax purposes, i.e. you cannot deduct tax against tax. I think one of the big 5 accountancy practices and Revenue were in disagreement over this recently.
I was thinking that too but there has been this furore over it recently, I reckon that by the time 2009 has to be filed, there will be a clear direction on it.