Found the answer ... :)
Added this to our pom:
| | <dependency> |
| | | <groupId>org.codehaus.jackson</groupId> |
| | <artifactId>jackson-core-asl</artifactId> |
| | <version>1.9.2</version> |
| | | <scope>provided</scope> |
| | </dependency> |
and then used:
@JsonTypeName("Body") and @JsonProperty("Def")
in the class files!