Hi Lashan,
I am also on the process of globally customizing our dashboards from items, projects and tasks.
I was able to customize the items and buckets(thanks for you and Ivanna's instructions) but unfortunately I haven't found the right obj type for projects and task dashboard which is also crucial in my customization.
I tried to search on those obj. type and found one:
http://scn.sap.com/thread/1805921
but upon trying, only RIH and RBH works, connection error returns when I am trying to use RPH.
Have you found the right values to customize the tasks and projects dashboards?
Thanks,
James