Hm right well I didn't doubt you'd given us the right version haha! First I'll check off what I've done, see if you can think of anything I've missed - I DO have a method that definitely works but I'll go into that shortly as it involves some editing in the CK - Alexander J. Velicky take note, I may have saved you an awful lot of time

I installed the new Oscape beta in a seperate folder, I also realised it was indeed generating files to the old folder so I changed that information. I deleted any reference to the old stuff (in fact I completely deleted the old oscape folder - and all temp files were being generated directly to it insofar as I'm aware), as well as all files within my worldspace's texture and meshes folders under the data files directory. I was going to use the overwrite function but decided straight up deleting all the textures and meshes was the foolproof option, so I've generated completely new textures and meshes based on the correct worldspace. I also checked the newly-generated textures in both .dds and .png format for the correct areas of my map - still came out brown.
I'm wondering if you guys are using custom textures or something? Custom textures have always worked in Oscape, just not the default ones from Skyrim.esm (unless, of course, you're generating using Skyrim.esm itself). Anyway, my easy (ish) method to work around the issue, which also allows Alexander to not have to retexture his whole mod for the time being -
- Open the CK, load up your plugin as the active one and also Skyrim.esm
- Go to Miscellaneous>TextureSet. This shows all the game textures used - since it shows everything type in "*landscape" into the filter field - this should isolate all the landscape texture references.
- Go down the list of landscape texture references and duplicate each one. It'll come up with the same name with "COPY0000" appended to the end. Don't bother renaming them it'll take forever, plus the default copy ID leaves it next to the original texture which is handy for the next bit -
- Now go to Miscellaneous>LandTexture - this is where the actual details of the texture's application are stored that the game itself references, additional stuff like grass etc. is in here, although you don't need to touch that right now.
- Open up each LandTexture and you'll get it's info, go to the dropdown box where it says "TextureSet" and select your copied alternate version of the texture (the one with COPY0000 at the end). It should be the texture directly below the default one. There's a huge preview of it below anyway so you'll know if you've got it right.
- Once everything's pointed at the right references everything should have a * next to it, indicating it's been edited. This should ensure the information is now contained within the .esp file directly.
- SAVE!
- Open up Oscape, point it at your plugin and generate the textures. If you need meshes, generate those while you're at it. I just generated DirectX colour/normals at the highest res it would let me (for some reason I can't tick 4096x4096 colour maps, is this just normal?)
NOTES -
Lscrub01 has no texture apparently (although you can always assign one if you fancy).
LSnowCobble01 references a texture without the prefix 'landscape', just go back to texturesets and find "snowrock01" and duplicate it.
This straight away generated everything spot-on in oscape. It should also leave the references in-place for skyrim itself since you leave the editorIDs that skyrim uses intact while merely pointing them at duplicate textures - here's some shots of it -
http://imageshack.us/photo/my-images/51/screenshot15ny.jpg/
http://imageshack.us/photo/my-images/641/screenshot16wp.jpg/
http://imageshack.us/photo/my-images/687/screenshot17jl.jpg/
http://imageshack.us/photo/my-images/35/screenshot18p.jpg/