Solution
LabVIEW and LabVIEW DSC do not at this time provide native OPC XML-DA support. Since OPC XML-DA is not natively supported, a wrapper is required to convert the OPC XML-DA communication to one of the supported standards for LabVIEW to interpret.
NI OPC Servers provides a OPC XML-DA Driver (as of NI OPC Servers 2013) to communicate with third-party OPC XML-DA servers, and converts communication to the supported OPC DA standard. Documentation for this driver can be found in the NI OPC Servers Driver Help.
Once the tags are loaded into NI OPC Servers, LabVIEW should be able to access the tags using an OPC Client I/O Server or a DataSocket Client.