Take care of the sense, and the sounds will take care of themselves.
About three months ago, I blogged about work-around solution to display right-to-left text in Silverlight. A bit after, Microsoft MVP Justin-Josef Angel begun to work on real solution. And today it's ready. I checked a code, posted on Microsoft development community site CodePlex and found it very nice and useful. So, if you have a problem with Hebrew, Arabic or any other RTL language in Silverlight. Use it (you can try it or see webcast as well), before manufacture's solution will come (and it'll come, I believe, some day). Very nice work, Justin!