I don't believe there is a way to transfer cached WUs in Seti Driver to use them in Seti Hide.
The best thing to do would be to set the Desired Cache Size in SetiDriver to 0, then let all of the cached WUs there be worked on, then when that's finished start using SetiHide. Both programs use different methods to cache the WUs, so i believe it is impossible to transfer them.
If you do not wish to continue crunching the WUs with SetiDriver, then you could just delete all the cached WUs in the numbered folders in your Seti directory, and start with SetiHide. Each WU is sent out many times by Berkeley anyway, because they expected WUs to go missing in action.
ConfusedBW