Allright, I just realize that this topic is a little bit a mix "wall properties" and "file structure".... Well I hope it's ok.
Next question: If one have been drawing a house with external walls, internal walls etc - with some defined properties for the walls - what if you suddenly find out that you want to change the properties for the external wall for example. Maybe you want your posts to be 75x225 in stead of 45x200, because your engineer (me...) told you to... Then you want to change core slice from 200 to 225. (there is still not timber in the walls, just to keep it simpel). If I do so, nothing happens - so it is not possible?? The program don't update the model with the new properties??
I thought this software was excellent... 
Well of course - if the software doesn't update such changes - then there are ways out of it:
1) Before you start drawing be sure your properties are as you want it to be.
2) If you still have to make changes, then make a new grond floor plan, number 2, draw the walls with the changed properties on top of the old walls, and then delete the old walls.
I am very new in the world of Dietrich's so sorry if there are some possibilities I don't see yet - but I am very fast learning.... 