Unfortunately, in the programs Cubase and Nuendo , you have the option of sending out an actual AUDIO click thru the outputs of your audio device. In DP and Logic, there are only 2 options for you to use when sending a midi click - either Internal speaker or MIDI.
There is NO audio pulse within these 2 programs so it will not come thru the US428 outs unless you connect a physical cable from the output of the MAC or your midi device into 1 of the inputs of the US428.