I have a new SharePoint 2010 site and have the Global Navigation on my publishing site set to show subsites and show pages. The subsites show on the navigation menu on top, but the pages I create do not. I am using manual sorting. Thanks.
This may seem overly simple, but it worked for me after spending many hours trying to fix the exact same issue you have.
Increase the number within the 'Maximum number of dynamic items to show within this level of navigation:' field in the Navigation menu. After I set this number higher (in my case, I had to set it to 30), everything showed up.
Simply: I was not paying close attention to the fact I was creating site pages or wiki pages rather than publishing pages. When choosing to create a new page, check where you are creating them. It will read "This page will be created in the Pages library". Pages should appear on the menu whereas Site Pages will not.
I don't know the details, but I had a similar issue. My onet.xml file missed navbar definition. I wrote a blog post about it: Can’t add a global site navigation link
<NavBar Name="$Resources:core,category_Top;" Separator="&nbsp;&nbsp;&nbsp;" Body="<a ID='onettopnavbar#LABEL_ID#' href='#URL#' accesskey='J'>#LABEL#</a>" ID="1002" />
Hope it helps, at least for others who encounter my problem.