what you can do in lite-c is get the d3d device pointer (using draw_begin(), I think) and then perform drawcalls using d3d interface functions like DrawPrimitive(), DrawIndexedPrimitive() or DrawPrimitiveUp() for example. note: the last one is more of a legacy thing from dx8 iirc. it's usually pretty bad for 3d geometry, since it always streams vertex data from the ram to your graphics card when drawing. still, I have used it successfully for 2d sprite drawing (since the vertex data is tiny in that case)
Alternatively, acknex has an engine function called draw_quad() which is basically the same but with some limitations. On the other hand, that way you don't have to fiddle around with d3d9 api stuff.

also, lite-c does not include d3dx9 helpers, afaik, and d3dxsprite sounds like another helper api that's built upon d3d9. (besides that, it most likely uses the same functions as mentioned above but provides a simpler interface for them). if you desperately want to use it you'd have to create a wrapper plugin dll for lite-c.

and lastly, if you're trying to draw sprites in you 3d level, I'm not entirely sure that's possible. acknex' limitations might be a problem here.

hope that helps