I actually found the fix for it and wanted to post it here so we don't have to surf the web looking for the answer. Hope it helps you guys.
I'm sure some of the players have had problems with the issue of the Ultimate honor and Endurance honor not showing up, even after you complete all the maps with maximum number of hard opponents. This is actually a bug in the game that was introduced in one of the patches, and not fixed due to EA's incomparable concern for its paying customers[*sarcassm*].
The bug itself is caused by the mistake commited by whomever added the new maps to the "MapsZH.big" archive, during the creation of a patch. The error is two entries in the "MapCache.ini" file. The two entries add the two C&C Generals maps "Armored Fury" and "Scorched Earth" to the file. These maps were official maps in Generals but were not included in Zero Hour. This is why people cannot get the Ultimate and Endurance honors. The game compares the completed maps in the "SkirmishStats.ini" file to all the maps listed in the "MapCache.ini" file, and since these two maps arnt present and cant be completed, people cant get these two honors.
The fix is also very simple, simply add these two entries to the "SkirmishStats.ini" file. You can find the file in the "Command and Conquer Generals Zero Hour Data" folder in the "My Documents" folder. Please make a back up of the "SkirmishStats.ini" file before you edit it since, it contains all your medals and win streaks.