May be i really didn't specified the problem properly.
I'll try to do it again.
I have 3 classes (class1, class2, class3).
Class2 is used inside class1 and class3 is used inside class2.
I want to call select for class1 and get all the data from the classes 2 and 3
in the result map of class1. The result map of class1 have matching prop
<result property="Class2.Test" column="Test" select="Class3"/>.
I can't create result map for Class2 cause there is no db table
related with this class. So in that situation I'm getting message:
unable cast class1 to class2.