I am running out to dinner so I don't have time to make examples, but...
Go to Design > Complex Profiles > Profile Manager (I hope this makes sense for the Greek version). This opens the editor for making and revising complex profiles. Draw a fill to define the profile, select whether it is to work as a wall, beam, and/or column and store the profile. It will then be available to draw with using the appropriate tool (select the profile method in the Info box or settings dialog). For further info read the manual. If you have any problems post back here.