UPDATED:
To include a soap ui project in maven include the plugin in your POM and configure it with the SoapUI project file (See below)
<plugin>
<groupId>com.smartbear.soapui</groupId>
<artifactId>soapui-maven-plugin</artifactId>
<version>5.1.3</version>
<configuration>
<projectFile>simple-test-soapui-project.xml</projectFile>
</configuration>
</plugin>
Looks like this plugin is not available in maven central, so you will have to include the plugin repository like so (in your pom or the settings.xml)
<pluginRepository>
<id>smartbear-sweden-plugin-repository</id>
<url>http://www.soapui.org/repository/maven2/</url>
</pluginRepository>
More information can be found here - Soap UI maven plugin
There is also another thread here