I have created a new .vpk HUD mod, have copy the mod to the addons folder, double clicked which claims it installed sucsessfully.
Load game, goto addons, "Delph's 48_9 Eyefinity HUD" addon avaiable, have selected it and clicked install (think i needed to install addon support which is a ~800mb download via steam).
Once the download was complete, I ensured the addon was listed still, which it was.
Started a co-op campaign, create lobby, start loading game....
error message "Server is enforcing consitency for this file: File is left4dead2/pak02_dir.vpk is not allowed to be moddifed."
I dont ever recall a pak02_dir.vpk file in the L4D2 folders, can someone else confirm these files are new?
I know for sure I have never touched them, I just wonder if they are anything to do with the ~800mb addon support that was downloaded via steam? :S
EDIT: after checking pak02 files sizes, they come to 817mb which is about the same as the addon support download from steam, so as these files are fresh they have not been modded... strange.
For anyone interested
here is my .vpk file should you wish to have a crack at getting this to work.
NOTE: This issue could be to do with the related issue that Valve are apprently trying to fix as linked in my previous post.
EDIT: Just completed a game file verify check, replaced 1 file (although it did not say what file, I am going to assume pak02_dir.vpk), game now connects to a server, however the HUD does appear to be as standard, not eyefinity shifted. :(