Can i call method async

 Hello,
I want to make a async call to a method. Is async call supported? I used dispatcher however no use.
The method to be called is following and I am calling this in a loop
for (int i=0; i < 5; i++)
{
AddItems(string s);
}
private void AddItems(string s)
{
} 
How can i do this best in Silverlight? 
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