Configuration of UUI for screenpops

Hello,
I'm working on popping SF screens using data collected by an IVR and stored in the UUI data. My issue is that I'm already using UUI for other items, so I'm trying to concatinate the UUI1, UUI2, UUI3 fields to the end with a ; starting the UUI data as configured in the callcenter. However, it does not appear to be working. Any thoughts or insight?

Thanks.

Doug