Dota 2 .bsp (map-file)

[Typhox]

I want to view & edit that BSP-Map file. It's version 0x17, so there seems to be no program to open it (yet). I have no experiences with hammer editor and so on, but I've read that you can decompile (?) the files to Hammer's file format. The program(s?) therefore are just a little outdated^^
What I'd like to have is some information on how that BSP-files are made up (even if it's an older version, maybe with example file for that version then), so I can hopefully understand it and fix it for the new version. On the first view (Hexeditor), it looks not that complicated and well structured.
Thank you.

[junk angel]

Here's quite a lot of documentation - though not sure if it has any updates for newer source versions
http://developer.valvesoftware.com/wiki ... ile_Format