Can Wiz750SR transmit to device that doesn't respond to ARP request

I need to interface the 750SR to a 3rd party device that doesn’t reply to the wizNet’s ARP request.

The 750SR is set up in UDP 1:N mode , Remote host =, Remote Port =0 . There are only 3 devices on the LAN connected via a switch

The 3rd party device sends out a UDP broadcast to destination IP = . The 750SR receives the packet and I reply with RS485 data, but the 750SR doesn’t transmit out the Ethernet. I’m assuming because the device didn’t reply to the ARP request.

The packet that needs to be sent contains all the network information for the device. Thus, the vendor is using there own custom version of a ARP

Is it possible for the 750SR to transmit this packet out using the Source IP or even a Broadcast IP?

Is this possible by modifying the firmware, if so, can you help me as to which part of the code needs to modified

Thanks for your help