Asterisk Dial不接受来自ARI的变量

Question

我的拨号方案（Ael）和ARI（C＃）如下所示：

AEL

sys_call 
{
  Set(CALLERID(NUM)=${call_from});
  Monitor(wav,${fname},mb);
  Dial(SIP/${num_to_call},30,m);
  UserEvent(Dropped);
  goto system,sys_wait,1;
}

ARI

RedirectAction call = new RedirectAction(astChannel, "system", "sys_call", 1);

SetVarAction num_to_call = new SetVarAction();
num_to_call.Channel = astChannel;
num_to_call.Variable = "num_to_call";
num_to_call.Value = number;

SetVarAction call_from = new SetVarAction();
call_from.Channel = astChannel;
call_from.Variable = "call_from";
call_from.Value = caller_number;

astCon.SendAction(num_to_call);
astCon.SendAction(call_from);


//Thread.Sleep(1000);// Sadly, it makes no diffirence
astCon.SendAction(call);

理论上，一切都应该正常，但Asterisk＆＃34;没有看到＆＃34;那些变量：Here's a screensoot。

有趣的是，如果我打破＆＃34;打破＆＃34;我的拨号方案，就像这样

Dial(SIP/явандал${num_to_call}жаж,30,m);

Asterisk会突然收到所有变量：Here's a screenshoot