I'm new to using InDesign so please excuse my ignorance. I was given the task of converting a textbook written in Microsoft Word into ePub format using ID. The original author did not use any character / paragraph styles when writing the text in MS Word. I was able to retain the italics and bold formatting using the Find/Replace function and replacing them with italic / bold character styles. But:
Thanks so much for any help.
You have been presented with an extremely difficult project because (1) you're unfamiliar with InDesign, (2) you're being prevented from using versions of InDesign which would help you the most (ID CS5.5 and CS6), and (3) you seem to be unfamiliar with EPUB creation.
The best thing I can recommend would be to go to Lynda.com and view Anne-Marie Concepcion's video on creating EPUB from InDesign CS5. She has workarounds for its limitations and it will probably answer most of your questions: