Can I disable alpha when baking textures? I have a particle system that adds some details to a texture. However when I bake the texture down, any area that is transparent makes the bake transparent, even though there is another object beneath the transparent one.
It appears that the default Bake Mode Full Render setting renders as if the Alpha setting under Shading (render tab) is set to Transparent.

When baking objects on to a texture, how can I disable alpha and just get the color as it would be in a render (reflections/refractions of the sky instead of Alpha pixels making holes)?

Note: I am making the particle system real and joining it first, so that it correctly renders and does not make the black silhouettes.
Id prefer an internal render solution if possible, but a cycles one is ok too!
Turn off transparency in the Render properties. In cycles it can be found under film and in blender render it can be found under shader. Or you could just add a plain as a background.