Hi Amro,
I am assuming that you presently have a Project with certain activities updated. What you need to do is set this present scheduke with its Actual Dates as a Baseline.
You do not need to assign this baseline to any Project. Simply restore this Baseline by clicking on the "Restore" tab in the "Maintain Baseline" box and you have a Project available in your database that has the Actual Dates now showing as your "Start" and "Finnish" dates.
Save this as a baseline again and assign it to have your "Actual Dates" now show up as "Baseline Dates" for the Project to which you assigned the baseline.
From my own experience, lets say you have Actual Dates for Activity A as Actual Start 01/01/2012 and Actual Finnish as 01/10/2012.
Activity B is a succesor to Activity A and is scheduled to start the very next day.
But when you follow the above procedure to get the Actual Dates of Activity A as Baselines Dates, you will notice that Activity B may be scheduled to start after a days gap and not the very next day as Planned in the program iin which you had upadated Actual Dates for Activity A. To resolve this I had reassigned a new Calender to the Programm and Scheduled it which realigned the Activities to start the very next day. If you want to use the same Calendar, simply create a similar new calendar and then reassign it.
I hope you find this usefull and is what you were looking for.
Regards,
Abdullah Merchant.