A_Van,
A-A has made data available to te investigation. A-A and the russian federation have been present at several meetings and have agreed to the findings. Then, suddenly, in the third and last meeting and response round, they have changed their story. All of this is well documented and you can read a summary of these events from page 94 onwards in the 'about the investigation' document
http://cdn.onderzoeksraad.nl/documen...igation-en.pdf .
You underestimate the expertise of TNO. They are very much tied to the Dutch defense industry which, although maybe not widely known, consists of several hundreds of companies. Missile simulations belong to their area of competence.
Although I reject statements based on secrecy as much as you do, consider that the head of the DSB has by now stated on record and publicly that there is secret evidence (from a classified infrared missile early warning system), that has also yielded a trajectory. It is in accordance with the published findings.