SQL Developer Data Modeler

Hi,

I would like to know if its possible for the ER Diagrammer Tool in Oracle Designer to produce a Link Entity that has a composite key made up of three keys. To illustrate:

I have 3 entities, COURSE, LECTURER, CENTRE

A Course can be taught at more than Centre
A Course can be taught by more than one Lecturer
A Lecturer can teach courses(same or different course) at more than one Centre

My normalization looks like this

Course_Code, CourseName, {LecNo, LecName, CentreName}
This will produce a Link Entity
CourseSummary (_CourseCode, LecNo, CentreName_)

How do I get the ER diagrammer to produce this table

I know that once I establish a many to many relationship in the ERD tool it will auto produce the link entity with the appropriate composite key, however I cannot draw a many to many relationship between three entities. Can someone provide a solution other than manually drawing the link entity and establish the 1 to many relationships.