Create a call simulator with ARI


I am quite new to ARI and Asterisk in general. I need to create a call simulator in ARI, to load-test our server. The simulator needs to start another ARI application and send DTMF’s. I am able to originate a call to the other ARI application, but the DTMF I send are not received by it. I am using AsternNET.ARI in C#, and I use the following code for that:

        AAI.client.Bridges.CreateWithId("TestBridge", "mixing,dtmf_events", "TestBridge");
        AAI.client.Bridges.AddChannel("TestBridge", AAI.CallId);
        AsterNET.ARI.Models.Channel c2 = AAI.client.Channels.Originate("SIP/12345678@", null, null, null, null, "KhlRecording", "dialed", "Eyal");
        AAI.client.Bridges.AddChannel("TestBridge", c2.Id);
        AAI.client.Channels.SendDTMF(c2.Id, "2");

Note: AAI is a class that I created to handle ARI.

Please advise what am I doing wrong.