Hi Omer,
For a given portal if you wish to move a tab from the admin menu and allow the user group siteadmin to view it do the follow:
select the item on the admin menu you wish to be accesible by the siteadmin.
Once the page has loaded take a note of the tabid in the URL
now select any other normal page on your site and click on settings.
now in the URL replace the number after /tabid/ with the tabid you took a note of earlier
You can now edit the page properties as you would a normal page.
So assign view privileges to the siteadmin group and select a location from parent page e.g. a page called site admin.
That should solve the problem for now.
John