I believe you did not follow me completely. Here is an example
http://www.uml-diagrams.org/sequence-diagrams.html that I would like to draw but I'm not able accomplish it. Either the tools to draw are not yet available in the beta or I'm not able to find the right tools.
Steps taken to generate the above diagram
1. Right click on the model and Add a sequence diagram
2. Toolbox shows basic, advance and annotation sub categories
3. In the basic category the only arrow available is message. I do not see a return message
4. As described in step 3, I'm not seeing all the options required to draw a sequence diagram under Basic, Advanced and Annotations sub categories in the toolbox
Here is the screen print of my toolbox

My Question: Is the sequence diagram tool box incomplete?