Glad you found them. I was typing this reply and some of it may not apply to your project now.
Kanth, the easiest way to download a terrset is to find one on the server and open a player arena.
For instance, avaetow has the winter 04 terrset, the wwi terrain has the wwi terrset. btw, avaetow isn't ready for prime time yet but you will get the terrset.
The terrain tiles you want, if you haven't found them, are the two 'big tiles' at the top under the TE Terrain tab.
Now for the bad news, the wwi terrain, "Waffle.res", in the wwi arena, isn't created with the terrset. The active area, just like "Tankland", is four custom objects that cover the underlying terrain which can be anything.
You can use the wwi terrset, but then you'll bang up against the three(3) mile distance between bases. The fields in Waffle and Tankland are closer then three miles.
I once looked at building a wwi terrain for Monday Night Madness myself, but I don't have the kind of time needed for 64 square miles of custom objects, not when it would be used in only one terrain.
If you still want to proceed, there are two or three routes you can take. They are too involved for a tutorial here. You can call Waffle, or contact me for help with a PM.