Hello Srini,
I'm not sure why you want to do this download / upload. Does the normal SU25 procedure not work for you? Here's an excerpt from the SU25 help:
Step 1
o If you have not yet used the Profile Generator or you want to add
all SAP default values again, use the initial fill procedure for the
customer tables.Steps 2a to 2d
o If you have used the Profile Generator in an earlier Release and
want to compare the data with the new SAP defaults after an upgrade,
use steps 2a to 2d. Execute the steps in the order specified here.
I think you want to avoid Step 1 and then proceed with Steps 2a through 2d. But, please explain if there's a reason you need to download / upload.