Note: from Project Designer version 1.24 and forward EcHo Plus and OsCar will no have this option. If you still need it in some of your installs, please install version 1.23.1.
Yes, but you will only be able to see a fixed illustration of the interface you designed for the buttons in Neets Project Designer. The buttons are interactive though with LED indication on change of state.
For a fully configurable GUI, you will need to use a SieRRa II, AlFa II or DelTa.