This question was already asked but never really answered. I already have silverlight and use it frequently on other browsers. I already have forbid microsoft silverlight unchecked in noscript options. I am trying to use netflix and it tells me to install silverlight, and yes I am aware this is a lousy way to use netflix.
There is no way to guarantee that Silverlight (like any other browser plugins) will not do direct connections instead of going through Tor. That's why they are disabled in the Tor Browser.
Using Silverlight with Tor requires using transparent proxying and a dedicated system made unable to learn the current location to preserve location anonymity. Silverlight being proprietary software, there is also no way to know what sensitive information it might leak that would make Tor useless.