Hi Lorenzo,
Here is some info;
Working with Software Images
This section describes how to archive (download and upload) software image files, which contain the system software, Cisco IOS software, radio firmware, and the web management HTML files.
You download an access point image file from a TFTP, FTP, or RCP server to upgrade the access point software. You upload an access point image file to a TFTP, FTP, or RCP server for backup purposes. You can use this uploaded image for future downloads to the same access point or another of the same type.
http://www.cisco.com/en/US/docs/wireless/access_point/12.3_2_JA/configuration/guide/s32mfw.html#wp1035507
Hope this helps!
Rob
