Web portal: Custom attribute display Eset from PersonAsEset to VI_Employee_Person_ResultAttributes

Hi,

I need to show on the list of employees (VI_Employee_Overview) a column where there is the first(is always just one) display name of the Eset taken from the table PersonHasEset.

I'm trying to do so customizing a new column on VI_Employee_Person_ResultAttributes.

Here a screenshot of  the configuration of the custom attribute but I get an error and I can't find any place where read how to do  that.

 

Someone can help me?

 

Mik