Since the vertical alignment of the text in pane tabs is not supported by Mozilla-based browsers at this time, you can use the TabView property to let the pane tabs look the same in all browsers. Just prepare images that include both the title and the icon of the pane, and set TabView="ImageOnly".
This information is available in our online documentation as well - you can find it below:
the Telerik team
Registration for Q1 2011 What’s New Webinar Week is now open. Mark your calendar for the week starting March 21st and book your seat
for a walk through all the exciting stuff we ship with the new release!