Dart Editor - Polymer - Express

[scne]

Dart editor scaffolds a web app with polymer, if I try to add express 0.1.6 into depedencies and start pub get I give this error into console

--- 3:40:10 PM Auto running pub get on /home/claudio/dart/HelloWorld ... --- Pub get failed, [1] Resolving dependencies... Incompatible version constraints on args: express 0.1.6 depends on version >=0.5.20 <0.6.0 polymer 0.12.0 depends on version >=0.10.0 <0.13.0