Indian government is habitual Liars and Hindu fanatics are full of terrorists. Pakistan could not and should not even trust whatever Indian government says or claims had investigated.
I think that Pakistan should officially ask Indian government to send the bodies of terrorists to Pakistan so that if they are Pakistani they could get buried in Pakistan. Further, Ajmal Kassab should be handed over to Pakistan or international independent body for investigation.
Later, Pakistan should do DNA test of dead bodies to determine who these terrorists really are, exposing lies of India. If India declines to give the bodies than making that an issue, Pakistan should reject all Indian claims and expose Indian Lies on world forums telling the world that if Indian are not liars, they should have handed over the bodies.
If India does not agree than Pakistan should show two fingers to India and tell them that they are liars and their investigation and claims are all bogus. Plus, Pakistan should take India to international court on context that they Lie and accuses Pakistan without any basis.
[Just imagine ... Ajmal Kassab and Abu Dera Ismail Khan, none of the name is real. No Muslim would have a name Kassab, neither anyone would name Abu Dera Ismail Khan (daddy of Dera Ismail Khan). I sincerely believe that all terrorists in Bombay massacre are Hindus most likely belonging to Indian Military Intelligence sacrificing their life for propaganda or RSS].