Merging varchar-Attribute (logical model) to varchar2(char) (physical model)

High, I'm using ER/Studio Data Architect 16.5.0 for designing our datamodel. I've tables with varchar-Attributes in my logical model. When I'm merging this tables to a physical Model (Oracle 11), ER/Studio creates varchar2(byte)-Attributes. Instead of a byte-semantic I need char-semantic (varchar2(char)). How can this be done per default in ER/Studio without setting each varchar2-column in the physical datamodel from byte to char?