5
Are you using firefox? I have found firebug to be a great help when debugging issues like this.
Your code appears as if it SHOULD work. There is nothing fancy that you are missing.
The difference between the two entries you show is that the "old school" way is to use tables to create layouts. That has changed and in "todays" world with CSS and XHTML they have gone to using DIV's. Either should work and since you are using a different template than the original one you could "show source" and see if the main menu is surrounded with a div or a table. If it is surrounded with a DIV then you missed something as it is using the original template. If it is using a table then it is using your code but for some reason not picking up your entries.
For debugging purposes while you are testing this out you could also insert a line such as...
Test Entry
Or even
Test Entry
to see if it is an issue with your links or something.
Since it is not a link you will likely get the same response with either line above but you SHOULD get something on the menu.
But then again you SHOULD be getting something on the menu with the code you have. Has to be something with how the template is setup. Double check your settings and make sure all the caches are cleared. Also make sure your file name is EXACTLY the same as the original found on your system. Same case and everything since filenames are case sensitive depending on the OS of the server.