Here it is:
. A referendum be held to check if people accept that Matadan was elected unfairly. This referendum will be monitiored by the Senate
2. After this, any openly criminal activities taken by any Osokan will be punished within the remit of the law on Lanzar, again under observation
3. A new set of elections will be held in order to legitimise authority on Lanzar, also monitored
4. After this, Lanzar will once more be a proper Imperial world.
Should any of the conditions be breached, the matter will have to be settled forcibly.
The main problem is that execution of this Treaty is likely to take many months..... So even uncovering some of Drakkon`s crimes will not mean an immediate breach of the Treaty. It is unlikely that Sartorus knows something that would make the entire Treaty invalid....