You have to build your component by selecting the description you like., something like: buildComponentFor: aModel ^((ModelClass descriptionFieldOne, ModelClass descriptionFieldTwo, ModelClass descriptionFieldThree) asComponentOn: aModel) addValidatedForm; yourself this example comes from this full post, it will surely help: http://onsmalltalk.com/programming/smalltalk/using-magritte-with-seaside/ In your case, I think you need to put a custom reference in your MAToManyRelationDescription (not sure though!) ... reference: MAPersonModel customDescription ... HTH, Cédrick