Since there is not a preset for Impulse in the Axiom you will need to program the Axiom manually to match the MIDI notes which Impulse uses to trigger the "play" function of the drums in Impulse. Follow the steps below to get the Axiom to play the individual sounds in Impulse.

Press the pad on the Axiom that you want to change. (i.e. C27)

Enter the edit mode of the Axiom. For Axiom 25's press the Advanced button or press the Data 1 button on a Axiom 49 or 61.

The Display will show a flashing music note with a MIDI note number.

Press the + or – key below the display to select the appropriate note. You can also type in the desired number using the keyboard notes. Note values are displayed as numbers.(i.e. 50)

Note that Impulse uses MIDI Notes:
60, 62, 64, 65, 67, 69, 71, 72 corresponding from left to right. Start with whatever pad you want to be the first one and enter 60. continue until all pads are used

Press the Enter Key to save the new value and repeat for the rest of the pads until you have assigned all the pads.