If you explode the guvnor war and edit $guvnor.war/WEB-INF/lib/components.xml you can edit the location where jackrabbit is expecting the repository config:
<property name="properties">
<key>org.drools.repository.configurator</key><value>org.drools.repository.jackrabbit.JackrabbitRepositoryConfigurator</value>
<!-- the root directory for the repo storage the directory must exist. -->
<!-- <key>repository.root.directory</key><value>/opt/yourpath</value> -->
</property>
You also need the right db driver jars in the AS/lib directory and can generate the repository.xml file in Guvnor (Administration->Repository Configuration).
Let us know how you have set it all up so far so we could help more.