Research & Development capital allowances

I am a bit confused as to where the 100% initial allowance on an R&D allowances (capital expenditure) should be shown on the CT600 itself.  Our software offers no guidance.  Being a capital allowance I would have thought it would figure somewhere in the capital allowance section (qualifying expenditure and allowances claimed) on the other hand s450 CA 2001 says the allowance is an expense of trade, so maybe it doesn't figure in the CT600 at all and just appears as a deduction in the tax comp itself.