If you need to tweak the styles of your ebook created with the iPad in mind then you can (with a bit of magic) set up Dreamweaver as a useful wysiwy(almost)g tool.
Dreamweaver, is, of course a web development and design tool. It will normally handle (x)HTML without any change. It will also allow you to edit other code and even XML. It will not edit the contents of a ZIP file (this is what a normal ePub package is) unless it is unpacked.
Publishers are under increasing pressure to develop workflows that enable their assets to be published to mobile platforms such as the iPad and the Kindle. Many book publishers are already using a variety of methods to create eBooks and where these equivalent print products are very text heavy (such as trade fiction) then this is very appropriate. But under what circumstances would it be better to create an 'app' rather than an eBook?
BBEdit version 10 has the ability to open the contents of an ePUB file. You can edit the individual components of the ePUB - which, of course is actually a ZIPped file, and then re-save.
Getting InDesign (CS5) to produce a decent ePUB format ebook is so problematic, that I sometimes wonder why we are bothering to use it at all! We could after all, use tools to build the components of the ePUB package by hand coding. Dreamweaver is a possibility and Sigil may also be a way to go.
However, one strategy may be to use InDesign as a starting point and then accept that we need to edit the resultant XHTML and CSS. This is the method that I am using, and I am promoting this method with my students.
After a few frustrating sessions recently, I thought I would note down a list of problems that can be solved. This may not be a comprehensive list...
In this technical note about a recent eBook that I created, I wrote about the need to include a hyperlink (back to the page where you came from), on the target page. It seems that this is no longer necessary with an ePUB inside the iBooks app on the iPad/iPhone.
Why? Because in version 1.2 of iBooks, it seems that a history of the navigation pathway is kept while the eBook is open. This is then utilised to display (at the bottom of the page) a 'back to page x' hyperlink, when the navigation items are showing*.