In the preferences menus for both the above mentioned browsers you can set them to report when queried, that they are whatever you wish.
Often sites will require IE for political or other reasons that have nothing to do with whether your alternative browser will work or not. So you are given the option of fooling the site into thinking it is IE so they will talk to your browser.
If on the other hand, there are true technical reasons, the use of active X scripts as an example, why IE is required then this will not help you.
The last time I checked IE 7 wouldn't run in Wine. IE 5, 5.5, and some support for IE 6 was what was available.
Insanity: Doing the same thing over and over and each time expecting a different result.
Democracy is 2 wolves and a lamb voting on the menu. Liberty is an armed lamb protesting the electoral outcome. A Republic negates the need for an armed protest.