Coming Soon feature does not support Beta. Please create a second submission (or Viveport ID) for your title and use that draft for beta testing. Having two Viveport IDs for your title will let you maintain your Coming Soon and Beta separately and streamline the submission process.
Please note and be cautious in not transitioning your Beta submission into a Create Production Release since this will create two listings for your title on Viveport. Remember to only update your Coming Soon for Create Production Release with your binary when you ready for our review team to QA and publish your title.
For transitioning from a Coming Soon to a Production Release please refer here for more details.