---QUOTATION--- Ok, how do I setup the CS SDK so that I can open the ported level in Level Editor? ---END QUOTATION---
You'll need to download the latest converter.exe (http://xray.codeplex.com/) to convert the map into LE format. The docs included explain how to do that, although it's a bit confusing as to where you need to enter the filepath to your CS install in converter.ini (look for section 3456_config). I'm also not sure whether you should use -mode le or -mode raw, but I guess it can'thurt to use raw.
If all goes well the level should exported to SDK_root\editors\rawdata\levels. You'll need to transfer all the level textures across too, I think you need to use converter.exe for this as well (to convert them to .tga), although I'm not sure, you may just be able to copy the .dds files across.
You'll probably need someone a bit more knowledgeable than me though, I've only dabbled a litte bit, was planning on trying some things out over the next few days.