[flexcoders] Learning to use RegEx Sting Replace

[Craig]

i know, it should be easy, the following code gives me:
Output: QuoteRSS

i am looking for it to give me:
Output:  IBM 100

can you tell me what i am doing wrong?

var str:String = "QuoteRSS: IBM 100";                   
var pattern:RegExp = /QuoteRSS/gi;
str.replace(pattern, "");
var result:Object = pattern.exec(str);
rssQteTitle = result.toString();

Craig