Inno Setup itself allows dual signing. The FB action “Build Inno Setup Script” doesn’t seem to be prepared for dual signing.
If I’m mistaken, which input would be required in the “Code signing” field?
From the signtool help.
http://www.jrsoftware.org/ishelp/index.php?topic=setup_signtool
The Setup section may also list multiple SignTool directives which will be executed in order of appearance. This can be used to dual sign (SHA1 & SHA256) Setup and Uninstall:
[Setup]
SignTool=mycustom sign /a /n $qMy Common Name$q /fd sha1 /t http://timestamp.comodoca.com/authenticode /d $qMy Program$q $f
;the /as parameter in the following SignTool requires a recent signtool.exe version and a SHA256 (SHA-2) certificate
SignTool=mycustom sign /a /n $qMy Common Name$q /as /fd sha256 /td sha256 /tr http://timestamp.comodoca.com/rfc3161 /d $qMy Program$q $f