Ok, get it to work:
	public void injectEvent(IClient client, RequestFunction function,
			AMFDataList params) {

		String streamname = params.getString(PARAM1);
		AMFDataObj question = params.getObject(PARAM2);
	
		IMediaStream stream = client.getAppInstance().getStreams()
			.getStream(streamname);
		if(stream != null) {
			getLogger().info("event injected into " + streamname);
			stream.sendDirect("question", question);
		} else
			getLogger().info("stream " + streamname + " wasn't found to inject into");
	}
				var JSONMetadata:Object = new Object();
				
				JSONMetadata.txt = 'Metadata';
				
				var nc:NetConnection = new NetConnection();   
				nc.connect("rtmp://localhost:1935/live");
				nc.call("injectEvent", null, "video", JSONMetadata);
2015-11-06	09:36:27	GMT+06:00	comment	server	INFO	200	-	event injected into video	-	-	-	10258.995	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-
But how to receive it on flash player?
Can't found event name that i should handle to process received data.

Thanks in advance.