XQuery in PropertyTransfer

Hello folks,

The described feature of SoapUI to be able to utilize XQuery statements in a PropertyTransfer TestStep is very tantalizing.  However, I cannot get it to work.  Do I need to have the Pro version of SoapUI to use the XQuery option in a PropertyTransfer TestStep?

Even returning a constant:
{
let $x := 1
return $x
}
does not seem to work.

I have confirmed that my XPath for the destination/target was correct using XPath for the source, but cannot get XQuery working in the source.  I get java.lang.reflect.InvocationTargetException with basically anything I've tried.

Please help!  Thanks.