I have created a parametrized lookup. The hidden ID field is a string, the displayed value is a string. When selecting the lookup in the attribute field that the lookup is to be assigned to, the return value of the lookup is Number . I believe this is the reason for the behavior I am experiencing - the value is not displayed when adding the attribute to the WBS view, it stays blank. The value is however properly saved in the database - this has been confirmed by XOGGING out the data of the entity. So how do I get the value displayed in the WBS grid or how do I get to change the lookup data type to String?