Hello guys!!
I am very grateful for all your help!!!
Thank you Ian, Nigel and Kurt - I have searched around those sites you mentioned. No success, but my thanks are no less! I do learn something from it like JetPhotos and Airliners sometimes have different photos - good for cross-referencing planes!!!
And just when I felt defeated then I saw Andi's miraculous message!!!
Thank you Andi for your help and your time!!!! I'm really speechless!!!
May I humbly ask the source Andi? Are the records from Acars or movements? Your personal record?? Could I have the privilege to know more??? I'm beyond impressed!!!!

And actually.... I have 2 more flights that I originally sorta gave up finding the reg number... but now I regain some hopes! It was my first ever visit to Oz!!!
(Time is local, scheduled time)
1999-08-30 / AE 801 / TPE-SYD / Arrival at 09:50 (TPE Departure: 8-29, 22:50)
1999-09-02 / AE 802 / SYD-TPE / Departure at 11:45 (TPE Arrival: same day, 19:00)
It would be really nice if anyone could offer me any form of help!
Thanks everyone!!!!