I handle a vast amount of Vietnamese text, so I run into this kind of issue all the time. (Note that I'm not not not suggesting that you use TNR in your layout, I just picked it because it's a font that I know everybody has that also contains combining accents.) But if you use your method to type an acute accent on a font that actually has a combining accent, and then select that combined e-plus-combining-acute glyph and change it to Minion Pro, then in the glyphs menu it'll show up as a precomposed e-with-acute. Your method did not work for me with Minion Pro, but it does work with Times New Roman. Minion Pro has an acute accent, which is what you get with option-shift-e, but it looks to me like Minion does not have a combining accent, which is what you'd need.

My whole job revolves around squeezing 40+ languages into InDesign, so I'm likely to reply to any post that is at all related to non-English stuff.

Can you tell us what keystroke(s) you're using, what operating system you're using, and what font you are using? InDesign CS5 is occasionally flaky about 'combining accents' but if your font doesn't have the combining glyphs I think it simply won't work.

Is this something that broke in CS5 and just needs to be fixed? InDesign is not allowing me to have the accent over the letter. I even looked it up online to get the correct keystrokes for the correct direction and accent. the backslash on your English-hardware keyboard has been replaced with the cedilla.

THis might not work for you because for all such keyboards you wind up needing to memorize that e.g. I'm not sitting at my Mac so I can't recall the precise steps but it's in the same menu area as the Character viewer. In your shoes, I might uinstall a French keyboard. I thought you just bumped an old thread with a post of a solution that doesn't involve typing accents.

How to type an e with an accent mark