Can tangram stretch textures on a polygon instead of tiling/wrapping it?

[vilinet]

Sorry, it is rather a question than an issue ( i hope :) )

I want to stretch a texture over a (rect) polygon, but it always ends up wrapping and tiling.
I tried to play with the texcoords, mapping using diffuse materials, but it always ends up with tiling just differently.

Thanks for any help!