Iskra MT880 and consereth. Cannot manage to read from device

Good morning everyone.
We are trying to read a certain number of Iskra devices from the field.

We already manged to read like 12 Iskra MT880 that are connected to the network through serial port (DLMS) and they are working properly.

2 of the devices are connected direcly with ethernet connection and looking from the official software we saw there is a "CONSERETH" flag enabled on it.

We saw there is already a topic on the consereth in this forum and apparently the consereth "protocol" can be summed up saying that it requires 3 HEX bytes before the payload of the DLMS request:

x03 x00 xa0

where x03 is a must and the last 2 are the big endian vesion of the lenght of the payload (len(payload) = 10 --> x00 x0A and so on).

We are using the python version of the library.
We decided to edit directly the final payload

In file:
\Gurux.DLMS.Python-master\Gurux.DLMS.Client.Example.python\GXDLMSReader.py

there is a function called: readDLMSPacket2

we modified if

def readDLMSPacket2(self, data, reply):
        if not data:
            return
        data = b'\x03' + len(data).to_bytes(2, 'big') + data
        notify = GXReplyData()
        reply.error = 0
        eop = 0x7E
        #In network connection terminator is not used.
        if self.client.interfaceType == InterfaceType.WRAPPER and isinstance(self.media, GXNet):
            eop = None

aaaaaand BTW the final result is this one:

before = bytearray(b'~\xa0\x08\x02\x97#\x93.\xbe~')
after = bytearray(b'\x03\x00\n~\xa0\x08\x02\x97#\x93.\xbe~')

TX: 11:27:41 03 00 0A 7E A0 08 02 97 23 93 2E BE 7E

we also scanned with wireshark the payload sent to the device and this this is it.

Unfortunatly, we can't still get any answer from the meter.
At this point we are not sure if we are sending the message to the wrong address or if there is a different problem.

As you can see they are reading the device at address 1.1.17 (well, in the consereth documentation it is said that the default is always 17) but we can't still get any answer.
We tried also other addressing mode (serial devices are reachable on - last 2 digit of serial number + 144) but we still get timeout message.

Do you have any idea on what we may be getting wrong?

Thanks a lot,