According to this reference, .daa is an extension related to the PowerIso application. This 2008 MacWorld article suggests an open source application - DAA Converter for OS X. The app page states:
DAA Converter is a free utility for converting DAA & GBI disk images
to ISO format so they can be accessed on your Mac.
DAA Converter is a native GUI application which wraps the command-line
tool, DAA2ISO/GBI2ISO, by Luigi Auriemma. It runs on Mac OS X 10.3
Panther or later.
I don't have any .daa files to test with, so I can't verify that this utility works. However, it's a GPL freeware app, so it wouldn't hurt to give it a shot.