How to handle EndDialog message when using Asynchronous Trigger Pattern?

I have Service A which sends a message to Service B when a update/delete/insert trigger fires.  Service B dequeing logic looks like:

declare @messagebody xml
	declare @messagetype nvarchar(256)
	declare @cg uniqueidentifier
	declare @ch uniqueidentifier

	DECLARE @messages TABLE(messagetype nvarchar(256),messagebody xml)

	begin try
		begin transaction;
			waitfor
			(
				receive top (1)
					@cg = conversation_group_id,
					@ch = conversation_handle,
					@messagetype = message_type_name,
					@messagebody = cast(message_body as xml)
				from MyPolicyQueue
			),TIMEOUT @receiveTimeoutMs

			if @messagebody is not null
			begin
				insert into @messages values (@messagetype, @messagebody)
			end

			select * from @messages
			end conversation @ch
		commit
	end try

ServiceB will end the conversation but afterwards, the queue now has an EndDialog message that never gets processed.

The intent is asynchronous handling of update messages with the trigger used as the event source.  Service B closes the conversation but trigger does not (It would probably be a very bad thing if trigger blocked waiting for EndDialog message response).  How do you handle the EndDialog message in this scenario?

The code is based on this example.

scott