Mass Effect 1: Assign powers to a single button like parts 2 and 3?

Although I played ME2 and 3 and did everything right, I have PS3, so I never actually played ME1.

I'm on the first mission, where you and Kaiden meet Ashley, and where Nihlus gets killed by Saren.

I'm so used to the button set up from the other two games, that I'm doing stupid stuff like throwing grenades when no enemies are around, and wasting medi gels when our health is already 100%.

In ME2 and 3, I just press the triangle button for my main power (cloak), and a quick tap on the trigger for the other (incinerate). So far, I can only use my power if I hold down the wheel, and select the power.

Is there a way to assign a quick button activate power in ME1? I looked online, but I keep getting long pages of stuff I'm not looking for.