You could also just try Unity? It uses CG syntax but CG is very similar to HLSL thanks to the fact that Nvidia made it while working on HLSL with Microsoft. Should be very easy to port a few functions and the only problem there is swapping out Unity's uniform/parameters when you port it into Oblivion (that said you would…
Minor experience in FX Composer. You can create a plane in a create menu at the top I believe. Assigning a texture is a bit different, you have to write a texture binding into your code and then compile it. FX Composer will pick this up and add this to the properties panel. I'm used to working with CGfx so what I say here…