the ecom100 only knows how to converse with a few things - other ecom100s, PCs, Modbus/TCP devices - and there's a protocol built into the ecom100 to do those.
the short answer is there's no way to have the ecom100 send raw data to a TCP port.
the long answer is there's no instruction in the PLC that can be made to handle the transaction required to get the data from the PLC through the ECOM100 to the tcp device. the closest thing is the RBE code you've already tried, but as you've found out, the ecom100 is sending a fully-formed, generic UDP packet, like you send to a PC. And it has our HAP wrapper around the data because you can request an ACK from the target device.