There is no way, India can provide evidence acceptable to Pakistan. Putting it another way, whatever evidence India comes up with, Pakistan will find them not up to the mark.
That is because, Pakistan cannot accept openly that its territory was used by terrorists to stage the attack on India. If Pakistan accepts this fact, then India will push Pakistan harder to act against the terrorists. Pakistan cannot do that. India may ask for their extradition. Pakistan cannot do that. So, Pakistan will continue to stonewall India.
However, India should not get frustrated by this and continue to apply pressure on Pakistan and the International community - by which I mean US, EU and China. Others do not matter much. Pakistan needs funding from these three to survive. India should protest heavily if it appears that they are likely to offer loans to Pakistan, before Pakistan resolves the Mumbai problem with India.
Alternately, India should offer Pakistan development loans (in Indian Rupees, not in US dollars), if Pakistan acts mercilessly against the terrorists (by extraditing them to India), and also cracks down on the Jihadi elements in ISI.