Ohhhhhhh, ok!!!
[env ( is the way the texture blends with the color of the survace (i.e. the one set by [color])!!! That's useless to my purpose: by blending mode I meant the way the object (with its resulting color however it results from its color and rexture) blends with its background
At the end I think I'll use glsl: with a very small and trivial modification to the "multitexture" example I've been able to add/multiply/subtract two textures, so I'll use that to blend a [framebuffer]ed image with another one as textures.