Sonar does not read Jacoco reports - maven

Question

I have a project whose Integration Tests are run by maven-failsafe-plugin and Unit Tests are run by maven-surefire-plugin.
I use jacoco to generate the coverage reports:
<properties>
<coverage.reports.dir>${project.build.directory}/coverage-reports</coverage.reports.dir>
<sonar.jacoco.reportPath>${coverage.reports.dir}/jacoco-unit.exec</sonar.jacoco.reportPath>
<sonar.jacoco.itReportPath>${coverage.reports.dir}/jacoco-it.exec</sonar.jacoco.itReportPath>
</properties>
[...]
<plugin>
<groupId>org.jacoco</groupId>
<artifactId>jacoco-maven-plugin</artifactId>
<version>0.5.7.201204190339</version>
<executions>
<execution>
<phase>pre-integration-test</phase>
<goals>
<goal>prepare-agent</goal>
</goals>
</execution>
</executions>
<configuration>
<propertyName>jacoco.agent.argLine</propertyName>
<destFile>${sonar.jacoco.itReportPath}</destFile>
<dataFile>${sonar.jacoco.itReportPath}</dataFile>
</configuration>
</plugin>
[...]
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-failsafe-plugin</artifactId>
<version>2.5</version>
<configuration>
<argLine>${jacoco.agent.argLine}</argLine>
</configuration>
</plugin>
[...]
<profile>
<id>dev</id>
<properties>
<sonar.core.codeCoveragePlugin>jacoco</sonar.core.codeCoveragePlugin>
<sonar.dynamicAnalysis>reuseReports</sonar.dynamicAnalysis>
</properties>
</profile>
[...]
When I run mvn install the Jacoco coverage reports are sucessfully generated.
But when I run mvn -mvn -Pdev sonar:sonar Sonar uses the Cobertura plugin instead of Jacoco.
I have tried:
1) Set jacoco as the default coverage plugin in Sonar settings [did not work]
2) Provide Jacoco parameters in the command line (e.g., -Dsonar.core.codeCoveragePlugin=jacoco) [did not work as well]
Does anyone have any idea? Thanks.
BTW I'm using Sonar 2.8