There should be support for launching apps that are not made be PortableApps.com. I have altered programs that I would like to be able to launch from the Platform. Also I have made some programs that I would like to launch from the platform. An easy option menu item could take care of adding the path to any executable or run any command.
You can use programs that are not from here. Go here: https://portableapps.com/support/portable_apps_suite#addingapps
Use the search box! Please!