GDC2016 plugin Message bus not working

I've been trying to use Max Preussner's GDC2016 plugin for remote control and have been able to discover remote device with plugin's ping pong mechanism. But i can not get RpcClient working. In the Messaging Debugger tool ,it display that all RpcClient calls have no valid recipient (dead letter). Any suggestions how to make it work?
https://answers.unrealengine.com/questions/669121/gdc2016-plugin-message-bus-not-working.html

[gmpreussner]

Hey foxhuntd, sorry for the delay, I've been pretty busy.

I'm afraid you're right. This is currently broken. Your observations about the message exchange are correct, too. The problem is that the RpcServer and the ConfiguratorGameMode use two different message endpoints. Because the RPC server never sent any messages to the client, the client doesn't know the server's message endpoint. When the client attempts to send a message to the server, the low-level UDP transport doesn't know where to send it to, so the message gets dropped.

In 4.12 we had a hack in IMessageRpcServer that allowed us to get the RPC server's message endpoint and send all messages through it. That allowed us to work around the problem, but it wasn't very elegant. In order to make this work properly, the Message RPC implementation really needs to be reworked a little, so all messages go through the same endpoint. It's on my to-do list, but somewhat low priority and might not get done before 4.19.

To make it work right now, you'll have to modify the Engine, unfortunately. First you need to make the FMessageRpcServer::GetEndpoint public, then you have to remove the version check in AConfiguratorGameMode::HandleMessage. Finally, you either have to add GetMessageEndpoint as a virtual public method to IMessageRpcServer, or to down-cast RpcServer to FMessageRpcServer.

[MatzeOGH]

I guess it is still broken as of 4.18.
Any idea when this will get fixed?

[KyleN97]

Has anyone been able to get this to work? When i added the virtual public method it would crash when trying to recieve a message, also how would i down-cast rpcserver to fmessagerpc server @gmpreussner ?
Thanks