Pretty sure this isn't proper behaviour, but I have a 404 page that I obviously don't want in my sitemap. I click the advance link in the meta data tab and change the sitemap's page priority to not indexed, however when I view the sitemap.xml file in my browser, the page is still listed.
Can anybody confirm this before I open a ticket? Not sure if this is normal. I'd assume when you set it to 'not indexed', it should be removed from the generated sitemap.xml file, yet mine still shows.
As this topic discusses, there is a bug which prevents this from happening.
The option isn't specific to whether the page shows up in the nav or not, what you want is to go to the 'meta-data' tab for a page, and click the 'advanced options'. There you will see how to rank the pages in the sitemap, but like I stated, the setting for 'not indexed' does not work correctly and all pages show up.
There is a ticket for this bug which will be fixed in the next release.