I would install the plugin using your start up script and store the plugin an a container field. the startup script would check for the plugin and if it's not there export the field contents to the plugin directory else continue startup script.
Else I would refer to the packaging software for directions on how to use there software.
If I have done my research correctly, the steps you are talking about happen on the database/server side correct? This would mean the client is already installed. I am looking to add the plugin during the install of the software. Also I am just using x-code to rebuild it, so if anyone has any knowledge or ability to help me that would be great.
So I got daring and tried a different approach to the task at hand. Instead of trying to modify the package and add things to it, I instead dug down into the content and found the PostFlight file. I then was able to change the permissions on the .fmplugin to mirror the desired permissions on the taget drive. I added this file to the Content folder of the .pkg, and modified the postflight script with the following line and it is now working exactly as desired. YEAH, GO ME!!!.EXTENSIONS_FOLDER="$TARGET_LOCATION/Extensions"if [ -d "$EXTENSIONS_FOLDER" ]thencp -r "$PACKAGE_PATH/Contents/YOURPLUGINHERE.fmplugin" "$EXTENSIONS_FOLDER/"fi