Applying custom styles to <a href> tags

Using FCKeditor 2.6.4, I have many styles that I use without any problems. I would like to allow my users to change the color of their links, including the underline. When they change the color of the text, the span tag affects the text, but not the underline. If I manually enter a style on the <a>, it works fine, but then the user would need to learn how to do this (ie. <a href="www.link.com" style="color: #red">text</a>. I've tried to create a custom style for elem=a, but that doesn't seem possible. Is there anyway to create a custom style for a link or change the color of the entire link?