Hi Chen,
I am sorry for the inconvenience. At the moment SBT runner doesn’t support project name as prefix for command. I’ve created an issue in our tracker http://youtrack.jetbrains.com/issue/TW-37967. You can start watching it to be notified as soon as it will be fixed. For now I can only mention ‘working directory’ option where you can set ‘backend’ and then ‘clean’ and ‘compile’ commands will be running there.
Regards,
Kate