private key missing after executing makecert command

i am trying to create the local certificate using makecert.exe.The command gets successfully executed and i am able to see the certificate in mmc viewer. But the problem is that the private key is not attached with the certificate. I am executing below commands respectively.I have tried to attach using certutil -repairstore my "serial no of certificate" but still it doesnt works.

makecert -r -pe -ss my -sr LocalMachine -n CN=RootCA -sv RootCA.pvk RootCA.cer

makecert -n CN=SignedByRootCA -iv RootCA.pvk -ic RootCA.cer -pe -ss my -sr localmachine -sv SignedByRootCA.pvk SignedByRootCA.cer