How have you coded the new units? Have you created an entire new faction with new sciences ie SCIENCE_UAN and SCIENCE_UK and have new playable sides or have you edited America, China and GLA to have different model units, like Defcon does. Theoretically if its the first it should be a week job at most, the second could take a lot longer since it will most likely be prone to getting buggered at some point along the conversion.
The real question is why? Zero Hour really doesnt add that much to Generals. There are some things you cant do with Generals, like the Listening Outpost, but there isnt that much you cant do with Generals that you can do with Zero Hour. Do you really need to change over, especially at this stage in development?
I might be able to help, if its option one and you've created new sides it shouldnt be that hard, but I can't commit masses of time to it since i'm already working on another project and also do have this annoying business of revising for my exams in January.
Zero Hour contains some key pieces of code that we need in order to incorporate some of our features.
I can't go into much detail about the workings of our mod, because... well, frankly, I am a complete idiot. Which is why, up until our leader left for a while, I was the Public Relations guy.
However, I can tell you that we've already removed the GLA and that we've added 2 new sides with sciences and stuff.