Have you also add the Maven/Ivy dependency and the repository?
Maven:
<dependency>
<groupId>org.vaadin.addons</groupId>
<artifactId>icepush</artifactId>
<version>0.5.5</version>
</dependency>
<repository>
<id>vaadin-addons</id>
<url>http://maven.vaadin.com/vaadin-addons</url>
</repository>
Ivy:
<dependency org="org.vaadin.addons" name="icepush" rev="0.5.5" />
<ibiblio name="vaadin-addons" usepoms="true" m2compatible="true" root="http://maven.vaadin.com/vaadin-addons" />
If this is not the solution, we need more informations about the problem to help you.