Siebel Raises Forecast, Stock Up 16 Pct.  LOS ANGELES (Reuters) - Business software maker Siebel  Systems Inc. &lt;A HREF="http://www.investor.reuters.com/FullQuote.aspx?ticker=SEBL.O target=/stocks/quickinfo/fullquote"&gt;SEBL.O&lt;/A&gt; on Monday said third-quarter revenue  would beat Wall Street estimates, driven by a rebound in  licensing revenue, sending its shares up almost 16 percent.