Finally I found you out in the same boat, thanks.

I filed I-485 on July 13, 2007 to NSC (PERM-EB2).By the way,how did you submit your (hard or electronic ?) copies of the related documents? My son is using Online Application to UC, there is nowhere to attach those copies. Maybe we don't need to care about this matter until we are asked to submit a copy of PR something like that. How do you think?
Thank you very much for sharing your valuable experience!