WindowsAzure REST API AddDataDisk "Error 404 : The resource service name hosted services is not supported"

Question

Hello I am trying to create a secondary disk attached to a Windows Azure LINUX VM.
I sent the HTTP POST message body
    <?xml version="1.0" encoding="UTF-8"?>
    <DataVirtualHardDisk xmlns="http://schemas.microsoft.com/windowsazure"xmlns:i="http://www.w3.org/2001/XMLSchema-instance">
        <HostCaching>ReadWrite</HostCaching>
        <DiskLabel>49192cf1-cd65-4750-83bf-1fb5a337493d-sdf</DiskLabel>
        <DiskName>49192cf1-cd65-4750-83bf-1fb5a337493d-sdf</DiskName>
        <Lun>1</Lun>
        <LogicalDiskSizeInGB>40</LogicalDiskSizeInGB>
        <MediaLink>https://accordscentralus.blob.core.windows.net/vhds/49192cf1-cd65-4750-83bf-1fb5a337493d-sdf.vhd</MediaLink>
    </DataVirtualHardDisk>
to the endpoint URL ( the url has been line split for clarity here only )
https://management.core.windows.net
        /{subscription-identifier}
        /services/hostedservices/54f84578testsmallubuntuw
        /deployments/9e8e1e43-d13a-4cfb-bd5b-19f6421f40dd
        /role/54f84578-testsmall-ubuntu-with-cosacs-volume
        /DataDisks
with the header
x-ms-version : 2014-05-01
and receive the same response no matter what I try:
404    Not Found
    <Error xmlns="http://schemas.microsoft.com/windowsazure" xmlns:i="http://www.w3.org/2001/XMLSchema-instance">
        <Code>ResourceNotFound</Code>
        <Message>The resource service name hostedservices is not supported.</Message>
    </Error>
The virtual machine has been correctly started, and is perfectly useable, but the secondary disk can not be created.
I have seen a few blogs and posts that say that I should not send the DiskName in the message but I need to be able to predict the name of the disk in order to be able to restart the VM with the correct disk.
Is there anyone that can help me to make sense of this.

Answer 1

Ok I have tested this again several times and have consistantly observed the following results.
The first time round for an new instance and a VHD that does not exist:
The request
POST https://management.core.windows.net:443/{subscription}/services/hostedservices/54f8cc27testsmallubuntuw/deployments/80388771-1cd2-4fe2-9637-6a06659840df/roles/54f8cc27-testsmall-ubuntu-with-cosacs-volume/DataDisks
<?xml version="1.0" encoding="UTF-8"?>
<DataVirtualHardDisk xmlns="http://schemas.microsoft.com/windowsazure" xmlns:i="http://www.w3.org/2001/XMLSchema-instance">
    <HostCaching>ReadWrite</HostCaching>
    <DiskLabel>d-80388771-1cd2-4fe2-9637-6a06659840df-sdf</DiskLabel>
    <Lun>0</Lun>
    <LogicalDiskSizeInGB>40</LogicalDiskSizeInGB>
    <MediaLink>https://accordscentralus.blob.core.windows.net/vhds/d-80388771-1cd2-4fe2-9637-6a06659840df-sdf.vhd</MediaLink>
</DataVirtualHardDisk>
Returns
HTTP/1.1 202 Accepted
and the VHD disk is created and attached to the virtual machine instance.
Inspection of the instance through the Windows Azure Portal using virtual machines->instances->dashboard we see the two disks attached to the instance.
The second time round, after terminating and deleting the instance and root disk VHD but not the extension disk VHD, whn creating and deploying a new virtual machine  instance to use the existing VHD created in the first case.
The same request is sent as above, but with a different instance, role and deployment information, and it returns the same
202 Accepted signalling success but the already existant VHD does not get used and does not get attached to the virtual machine instance. In fact no extension disk gets attached to the instance at all.
Inspection of the instance through the Windows Azure Portal using virtual machines->instances->dashboard we see only one disk attached to the instance.