Adding attributes to DDS topics

[Gordon]

I have been trying out the 30-day-trial versions of Enterprise Architect along with the MDG DDS Add-In, in advance of purchasing the Professional edition proper, but I'm having a little trouble implementing my intended DDS data structure.

I was hoping to build a basic DDS data structure where: my data messages (attributes) are collected together under DDS Topics, which will themselves be grouped under Classes and Packages. From the example DDS projects that I've downloaded, I can see how to apply QoS values to the DDS Topic level, but I have not been able to add attributes to each Topic.

To clarify; I am using attributes as the individual data messages passed between the components of the system. Is this a normal use of DDS/middleware attributes and topics within EA? Is it possible to group attributes under Topics in the full version of EA and the MDG DDS Add-In, and if so, how is this done?

Thanks in advance for your help,
Gordon