You need to be rooted and have busybox for this:
1. Extract the build.prop from the 7z file.
2. Connect the phone via USB, select mass storage mode if prompted, and copy the build.prop file to the sdcard (I am going to have to assume root of the internal sdcard for the sake of the commands below). Then disconnect USB storage so that your phone can see the file you just copied over.
3. Open a Terminal Emulator session or have the phone in debug mode, and start ADB shell, and do the following:
# mv /system/build.prop /system/build.prop.bak<- Or use rename in Root Explorer
# cp /sdcard/build.prop /system<- Or use copy in Root Explorer
# chmod 644 /system/build.prop<- Or fix permissions to rw-r--r-- in Root Explorer
# chown root.root /system/build.prop<- You have to do this in the Terminal or an ADB Shell. If you get an error about unknown user/group, try chown 0.0 instead of root.root.
Now close the Terminal Emulator session. Double check ownership to root.root, and permissions to rw-r--r-- in Root Explorer or using ls -l /system/build.prop first if you are paranoid. If you are really anal, open the build.prop file you just copied over in a text editor, and make sure it says I897UCJF6 instead of I897UCJH2.
4. Start a task manager and kill the market app (if running).
5. Press the menu key while on home screen and go to Settings -> Applications -> Manage Applications. Hit the menu key again, and change filter to All Applications. Then select Market, and clear the cache. I also cleared the cache of AppBrain while here, not sure if it made any difference, but won't hurt to do it.
6. Reboot the phone and use the Market for a little while. Install and uninstall a couple of apps. Once the cache rebuilds, the formerly missing apps Market pages will be visible, and available for downloads and show updates. When I first went in the Market, the apps were not there, but it took a couple times hitting the google server to get it all sorted out.