Need help with Mbox2 Mini setup.

[playgirist]

I have Mbox2 Mini and trying to use Keystation 88es as a MIDI controller.
I figured out that there isn't any MIDI port on Mbox2 Mini. Therefore, I just connected Keystation88es to my computer since there was a USB MIDI in/out. Is this setup correct, without having the MIDI controller connected directly to Mbox2 Mini?

With the above setup, I tried playing my keyboard on PT. However, I couldn't hear any sounds. Rather, I could see the signals in the fader, in the mix window. I don't have a monitor speaker so I plugged in my computer speaker (Apple Pro Speaker) using a 1/4 inch TRS adapter. Do I need to get the monitor speakers to hear the sounds? Also, is there a way to use Mbox2 Mini as if it were a default soundcard? I need help :/

[DigiTechSupt]

Therefore, I just connected Keystation88es to my computer since there was a USB MIDI in/out. Is this setup correct, without having the MIDI controller connected directly to Mbox2 Mini?

That's correct.

With the above setup, I tried playing my keyboard on PT. However, I couldn't hear any sounds.

What are you using to play back the MIDI data? MIDI is just data - it's not the sound itself, so you need to use a softare synth or sampler or and external hardware synth to hear anything.