man, really, i didnt understand why u want to convert fbx mesh to block.in my estimation, its unnecessary.

as far as i know, block and mesh are different things. As a result of this ,texture problem appears.

i think, u can create this road in wed, by the help of vertex move,edge move,face move tools (for trapezoid shapes) and texture settings dialog box.

hope it helps.
(anyhow, wait advanced user contributions)