Differences for printer driver for Windows XP 64-bit release and beta version

Our printer driver installation utility seemed to work till the 64-bit
XP Beta version. Our setup wizard has always worked thinking that the
OS known driver files would be lying in <root drive>\IA64 path. Now, In
the final version of 64-bit XP service pack 1, It seems that the
driver.cab file is lying in I386 directory. I have few questions
related to it and hope someone will help me out here.
1. Is the driver.cab file destination would be based on whether the
system is a x86 based system or amd64 based one ?
2. Has the destination files of drivers also changed in the release ?
3. I tried changing the source path to where my driver.cab is residing
currently on my machine, Now its looking for sp2.cb. My system doesn't
have a sp2.cab but it has a sp1.cab (its service pack 1). Can someone
explain what could be the reason here.

Thanks a lot,
Ashish