Car tax (CO2 based) on older vehicles

Hello, I have a question about the taxation of older vehicles according to the new CO2 based tax. Specifically it is about a 1.4l diesel from 2005 with EURO4, without DPF and a CO2 emission of 112g. After the old engine capacity tax this vehicle would cost 216 EUR (as April 2011). If the vehicle were taxed after CO2 emissions it would be 133 EUR. The question now is whether there is a possibility to tax the vehicle according to the new rule although it was registered for the first time in 2005. Is there possibly a cheap check? Greetings. Sebastian