confirming an siRNA gene knockdown using qRT-PCR - (Nov/27/2009 )

I use qRT-PCR to determine if my gene of interest has been knocked down using siRNA. Do my primers have to be designed to the part of the mRNA that is cleaved by the siRNA or can it be designed to any part of the mRNA, i.e. does the mRNA completely breakdown after its been cleaved by the siRNA?

the primers can be designed to any part of the mRNA, it will all be cut up