I tried to save XML data using a POST statement to config root and then confirm it was there using GET retrieval request. This allow occurs using 'accept':'application/json'

#POST http://localhost:8080/restconf/config/

1. Actual Response == Exepxted response

HTTP STATUS 204

then check want is in the configuration data store.
#GET

http://localhost:8080/restconf/config/opendaylight-inventory:nodes/node/id1

1. Actual response

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<node
xmlns="urn:opendaylight:inventory">
<id>id1</id>
</node>

1. Expected response:

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<nodes>
<node
xmlns="urn:opendaylight:inventory">
<id>id1</id>
</node>
<nodes>

1. 1. Notes,

GET http://localhost:8080/restconf/config/opendaylight-inventory:nodes/
showed the nodes container as expected.

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<nodes
xmlns="urn:opendaylight:inventory">
<node>
<id>controller-config</id>
</node>
<node>
<id>controller-config-xml</id>
</node>
<node>
<id>id1</id>
</node>
</nodes>

TEST ENV

org.opendaylight.controller.version = 0.1
org.opendaylight.controller.build.scm.version = 78fec1c1c5a3720bd48d1044703824626f08b5d9
org.opendaylight.controller.build.user = jenkins-controller
org.opendaylight.controller.build.workspace = **********
org.opendaylight.controller.build.timestamp = 1409283738738
org.opendaylight.controller.build.machine = **********
~

No special configuration was needed to replicate this bug. During this test I had 2 controllers ('controller-config' and 'controller-config-xrvr') configured but I don't believe that this affected the results.