there are 2 ways to achieve this
1. Create a scheduler BPEL program (using quartz) which will write the trigger file in the FTP adapter polling directory and the FTP adapter should get activated on the trigger file.
2. Create a BPM process with Timer start event to write the trigger file in the FTP adapter polling directory.
SOA Suite 12c will expose Oracle ESS as the scheduler.
ESS will allow you to schedule soa composites / OSB services etcand allow you to enable / disable them based on jobs, which is what you desire.
12c SOA Suite is expected later this Summer.