I do something similar on one of my sites. The following should work. You need to exclude /software/ from the first rewrite. Each rule uses [L] which means last rule - i.e. don't bother processing any more.
Code:
RewriteCond %{HTTPS} !=on
RewriteCond %{REQUEST_URI} !^/software/.*$ [NC]
RewriteRule ^(.*)$ https://www.domain.com/$1 [R=301,L]
RewriteCond %{HTTPS} =on
RewriteCond %{REQUEST_URI} ^/software/.*$ [NC]
RewriteRule ^(.*)$ http://www.domain.com/$1 [R=301,L] Ben