Dictionary<string, string> parms = new Dictionary<string, string>();
parms.Add("twitter_name", "nullstyle");
var result = FastPass.script("lmwjv4kzwi27", "fiei6iv61jnoukaq1aylwd8vcmnkafrs", "scott@getsatisfaction.com", "Scott", "nullstyle", false, parms);

Output:
<script src="http://getsatisfaction.com/fastpass?email=scott%40getsatisfaction.com&amp;name=Scott&amp;oauth_consumer_key=lmwjv4kzwi27&amp;oauth_nonce=wpiZFNjJxFKq8z9V3L6uYoff5p2m62mXMBJClzm9A&amp;oauth_signature=V99fKTkbGx4jm4GcIWNffClv97U%3D&amp;oauth_signature_method=HMAC-SHA1&amp;oauth_timestamp=1229463267&amp;oauth_token=&amp;oauth_version=1.0&amp;twitter_name=nullstyle&amp;uid=nullstyle" alt="" />