just unmark the "Enable Web Installation" feature in your SB project and recompile. SetupBuilder will generate a single-file installer with the same .exe name.
I already did that shortly after I posted my original message. I simply could not afford wasting the email campaign resources by pointing interested respondents with the Web Deploy version.

Basically I am no forced to create a response arrangement where I send the respondent a HTML page that is not linked to any of my web site's pages. In this HTML file/page they will find a download link to the non-Web Deploy version. There is no way that I can make the 400mb EXE public as a result of this problem, because as I mentioned earlier, EXEs that are linked in public HTML files get downloaded by search engine spiders.