Les. We go through this quite well so I am happy to cover off a few points here.
We took a matrixed approach to processes and systems and identified the number of repitions required to pass. The aim being to ensure that the processes worked and the systems supported the processes on multiple occasions. Make sure you cover core, exception and support processes.
The most important thing was aquisition of 'friendly' customers that would assist us by jumping through a few hoops to ensure we covered as many bases as possible. Again these covered core, exception and support processes. An incentive helps here too as does a questionairre.
Also, a proper framework is needed to ensure that a centralised view is taken to resolving production issues. These could be process or systems.
Finally, a reporting mechanism that identifies to the powers that be that we have run through the specified processes and systems, obtained the right system reports and therefore have a high degree of confidence that we can lauch this to the general public.
Hope this helps. Let me know if you want further info.