How to turn off ligatures in Mac 2011 PPT?

[muaythai]

I'm building a deck in my Mac version of PowerPoint, and using my brand's typeface called Prelo. Since my version of Prelo is in the OpenType (.otf) format, it supports ligatures. A ligature is a typographic feature where certain letters combine into each other, making one character. Like AE being rendered as Æ.

I love typography but I don't want PPT automatically making ligatures for me! I've attached a screencap of two probelmatic ligatures I'm getting now: "Th" and "ff."

Can anyone please tell me how to disable automatic ligatures?



Thanks!