Article 7 of the proposed Statues of the MH17 International Tribunal may hold the answer to why Russia so adamantly opposes its creation:
Irrelevance of official capacity
This Statute shall apply equally to all persons without any distinction based on official capacity. In particular, official capacity as a Head of State or Government, a member of a government or parliament, an elected representative or a government official shall in no case exempt a person from criminal responsibility under this Statute, nor shall it, in and of itself, constitute a ground for reduction of sentence.
Immunities or special procedural rules which may attach to the official capacity of a person, whether under national or international law, shall not bar the Tribunal from exercising its jurisdiction over such a person.
Below is the full text of the draft Statutes for operation of the proposed MH17 Tribunal.