If it's a production LPAR you have to use the existing scheduler, for example CA-7 or TWS.
O a development/test LPAR without any adequate support I would configure the Windows Task Manager to submit a job via FTP which executes the REXX program.
If you are only interested in the status and output of some jobs there is no need of executing another job. FTP is capable of retrieving job information from JES spools directly.
There are 10 types of people in the world: Those who understand binary, and those who don't.