Longer DTMF Tones?

[rjmwx81]

Is there any way to set the phone to send longer DTMF tones when I hold the keypad buttons down during a call? On my previous phone it was very easy just to set "long" keypad tones but so far on my Optimus G the only thing I'm finding is an option for keypad tones on/off...nothing to change the length. Certain automated phone systems I call are not recognizing the tones.

 

[B. Diddy]

From what I've read on various support pages for the Optimus line, there doesn't seem to be a way to adjust the duration of the tones.