1.7 allows you to set/update file IDs by adding a line for the file to the [repackFolder]\fileIds.txt file, of the format:
[full file path]=[file id]
(should also work when creating a patch too)
Extracting an index will create a fileIds.txt listing each files ID in the same format too.
ModLoader 0.2 will also merge fileIds.txt from each mod installed (currently doesn't detect conflicts where two mods both change the ID of a single file though)
Thanks to Grinderkiller for finding that IDs are important, I never actually thought the game used them but he found that weapons (and maybe more) rely on them, hope this update can make modding them easier for you all :)
Changes in 1.7:
- allow using fileIds.txt to set/update file IDs
- extracting now creates a fileIds.txt listing each files ID
- ModLoader 0.2 merges fileIds.txt from each mod installed
Changes in 1.6:
- add support for extracting & rebuilding .pindex/.patch files
- add --createPatch option for creating a .pindex/.patch pair from a folder.
Changes in 1.5:
- new method used to extract files, so it should use a lot less memory now
- switched to SharpZipLib instead of Zlibnet