SSRS boolean parameter Yes and NO instead of True and False in prompt area

Hi everyone,

I am using SSRS 2008
As i want to have the Yes or No     instead of       True or false in Radio button  Boolean parameter in prompt area.

Can any one please suggest me what i need to do i n order have YES or NO in the Radio button  In Prompt area .

And there is no place where i can write the expression. Please help me.

Thanks in advance to everyone.



Affu
SSRSWORLD