From the version 1.20, you can turn on/off an iOS device's screen using the power button in the multimedia keys window. However, the 1.20-BETA doesn't have the feature.
Here is the third Beta version that incorporates the feature: https://download.acrosscenter.com/AcrossSetup64-3.zip You need to remove the previous BT pairing with your iOS devices and pair again to evaluate the feature.