To fit the flat plate to the wall I used these...
http://www.oaktreepackaging.co.uk/tech.asp?item=Wall%20Bolt
The Nut is driven by a 10mm driver - the threaded diameter is 6mm
You might buy the largest wall bolt that fits the holes.
The flat plate that attaches to the TV set uses 4mm screws as I recall.
Peccavi
January 2011