I have looked at the Ant Radio Service code for sending an acknowledge message, and think I know why you are getting an exception thrown. The ANTSendAcknowledgedData() function requires 8 bytes of data to transmit, if less are passed to it, an exception is thrown. Try changing
byte[] commandArray = new byte[7];
to
byte[] commandArray = new byte[8];
Also the reason PARAMETER_TX_NOT_RX (0x10) doesn't receive beacon messages is because it configures the channel as a Master. Assigning a Slave channel will make it search for a Master (Broadcasting beacon messages)