Azure Storage CloudBlob.Properties are not initialized when using GetBlobReference()
I believe you have to make a seperate call to fetch the attributes/metadata. After you have the blob referrence, issue the following line to retrieve the attributes.
cloudBlob_GetBlobReference.FetchAttributes();
This relates to the Java SDK. But having a CloudBlob derived CloudBlockBlob object, you may need the CloudBlob.downloadAttributes() call.