How to get acked and unacked in SSL buffer access mode?

Hi, I am using BG600L-3m and I would like to know if there any AT command for SSL connection to inquire about the acknowledged data? is there a command like in TCP (AT+QISEND=0,0):

+QISEND [0], <acked_bytes>[1], <unacked_bytes>[2]

No, I suggest you return ACK data via SSL server