Encrypting property in etc/*.cfg file is one thing. The other is to decrypt it where it's actually needed.
If you're defining your datasource in blueprint XML file (and I guess you do), please read "Using encrypted property placeholders" section of http://karaf.apache.org/manual/latest-3.0.x/#_encryption_service. Even if it's about Karaf 3.0.x, it should work with Fuse as well.
Thanks for your answer
I'm not using blueprint, the datasource is used from java code (running in Karaf as a bundle). I think not possible to make a blueprint, because it's a legacy code (jar) integrated in a camel processor, and we need to use this code as black-box.
The datasource is being accesed like a standard JNDI datasource from this legacy Java code:
Context context = new InitialContext();
dataSource = (DataSource)context.lookup("osgi:service/jdbc/cmmConfigDS");
Connection connection = dataSource.getConnection();