Mesh Terrain Texturing

This is probably a simple one for those who have used mesh terrains, but I'm non-plussed.

Before now I've been using 2 different textures on a Blitz terrain -
EntityTexture hEntTerrain, hBmpTerrRock, 0, 0
EntityTexture hEntTerrain, hBmpTerrGrass, 0, 1
- so that the grass texture is coloured very subtely by the rock texture.

Now I have to use a mesh (.X) terrain.

But the EntityTexture code do not seem have the same effect.
The grass texture becomes very much darkened, and the striations in the rock texture can't be seen at all.

Not a nice effect. How can I get the sublety of Blitz terrains on a mesh terrain?

Oh, come on guys.
Call me an idiot if I'm missing something obvious, but someone _must_ have conbined two textures on a mesh terrain.
Anybody? Sswift?

Did you set the texture blend mode?

Yes, I've done all the obvious stuff.
I really need a reply from someone who's already done this, preferably with a snippett of code to show what settings were used.
Cheers.