Encounter creation fails for Obs mapping with ConceptMapping instead of Concept uuid

With reference to this issue https://issues.openmrs.org/browse/RESTWS-468 :

Using Concept mappings instead of uuids for posting data to OpenMRS via REST fails with error here pastie.org/101068832.

However same call successfully passes when Obs are mapped with concept uuids.

A test class is attached which have two tests
1- with Obs mappings with concept uuids
2- with Obs mappings with concept mappings as defined in ticket earlier. This throws RuntimeException.

The test class needs to have openmrs url, username, pwd and an existing valid encounter type. First 4 class properties would need to be changed to reflect this.

The version of module required for expected Rest Web Services - 2.9. The test doesnot work on OpenMRS demo server as it has REST module version 2.6