How to adding custom lightmaps in map?

How to adding custom lightmap textures in map and, editing, extracting lightmaps from map?

Is the question about including/extracting custom content with/from a map or editing the actual lightmap data?

This question about VRAD lightmap editing ways (Lightmap data editing).
-Edit: Sorry for my English.

Its impossible to edit lightmap data outside of hammer.

VIDE’s BSP Info tool can be used to extract and replace BSP lumps.

Lightmap Lump Structure

As VIDE does not have lightmap editing abilities, a hex editor or other such tool must be used instead.

But BSP format is open source format, its not imposible.

[editline]4th September 2012[/editline]

Do yo know lightmap texture editing tools etc. ?
And I know Vide’s PAkfile lump editor, but I not know editing ways.

Only VRAD. What is the goal to be accomplished through manual lightmap editing?

For, More realistic soft shadows, realistic radiosity, AO etc…
My idea is Render To Texture outputs using for lightmaps…

And I tried Multi lights in one position for Multisample soft shadow lights in Hammer, VRAD is crashed…

Brush lightmap detail may be made more accurate by decreasing the lightmap scale (thus increasing luxel density) in the Face Edit Sheet dialog.