You need a change of tactics. These attacks on civilians like the bomb in the train on Monday are quite insane, inhuman and will not further your cause. If you want to claim to be the sole representatives of the Tamils, a claim that is far from accepted, at least try to act the part and behave with responsibility. A terrorist is loved by no one and the tactics of terror only provide cover for the harsh repression of civilians.
Denying responsibility for the various atrocities or maintaining a silence will not work, you have little credibility and your words will be doubted, even if by some possibility you were not actually responsible for the crimes committed.
If you must fight, fight the soldier on the battlefield, not the civilian in the town or village, but remember the maxim that all wars are political. A war for the sake of war or a war of attrition serves no one.
Better still, return to talks. That is what the people wanted and would have voted for had they been given the opportunity in 2005.