Last week, we had the author of TDD for a Shopping Website LiveProject. Friday at 11am Ranch time, Steven Solomon will be hosting a live TDD session just for us. See for the agenda and registration link
You cannot have xs:element having a type attribute defined
and then followed by an xs:complexType or xs:simpleType for that matter, you can only have a construction one kind or another. That's what the error message meant.
The prime way of doing it is to do an extension of a complexType element with simpleContent. Like this.
There may have shortcut and there does, but the idea is there in an elaborated display.