Reaching extensions behind key system


When calling out from asterisk I’m facing problem in reaching individual extensions behind a key system.

From the asterisk i’m trying to dial a number to reach a key system and then sending DTMF digits to reach its inner extensions. The dial plan looks like below,

Dial IAX2/service_provider/15556667777|30|mD(102)

In the sample dial plan above i’m trying to reach the key system (by dialing the number 5556667777) then to reach its inner extension by passing DTMF digits 102 (here in the example by using flag D).

The call reaches the keysystem properly and plays different menu messages but, the call is not reaching the inner extension - 102.

Can anyone help me here?

Thanks in advance.