Hi Diego,
You can override styles in IE 7 using the IE7Specific.css file. Note that this file is not to be inlcuded in the list in the style.config file, it must live in the skin folder and it is not subject to the same css combining/minimizing/caching as the main css. The IE specific files are added into the page using IE comments so they are extra css files specific to IE but are ignored by other browsers. They are addeed to the page below the main CSS like this:
<!--[if lt IE 7]>
<link rel="stylesheet" href="http://www.mojoportal.com/Data/Sites/1/skins/mojosite-brightside3/IESpecific.css" type="text/css" id="IECSS" />
<![endif]-->
<!--[if IE 7]>
<link rel="stylesheet" href="http://www.mojoportal.com/Data/Sites/1/skins/mojosite-brightside3/IE7Specific.css" type="text/css" id="IE7CSS" />
<![endif]-->
so IESpecific.css is for IE6 and IE7Speciofic.css is for IE 7.
Its possible there is already something in the IE7Specific.css that is causing the lionks to not be styled correctly or you can possibly fix it using this file.
Hope it helps,
Joe