Key Programing

[kwin100]

Hi, I purchased an after market key for my 530i, I got a locksmith to cut it using the old key as a template.
Following the instructions I programed the key and the locks went up and down which was stated.
However the imoboliser does not recognise the key as ignition lights come on but will not turn over the motor.
The key does everything else but start the engine.
Any help would be greatly appreciated.

Kevin