iphone sdk How to play DTMF audio file during a phone communication

I need to create an application that interact with a telecom company. The end user make some choice in the application and after that we compose a number that include DTMF tone after a pause (,) to call the corresponding departement. But my problem is here: composing DTMF digit take too much time about one second per digit. It's very very to slow if we need to add 10 DTMF digit.

SO my question: Is it possible to record the x DTMF's (0-9) in audio files and play them fast within the audio stream of the call t开发者_如何学Pythono speed up the sending of DTMF's?

Edit: Maybe my question was not explained in a very clear maneer but i don't create DTMF tone myself i just add some number after a pause. like that:

[[UIApplication sharedApplication] openURL:[NSURL URLWithString:@"tel:003299887766,1234556890"]];

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At the moment it is not possible to send shorter DTMF tones from iPhone.

One way to say bout it to apple is to use the feedback form: http://www.apple.com/feedback/iphone.html