Interactive steel designer

Hi everybody, 

I was modeling a steel-Aluminum  structure in STAAD and when I tried to use the interactive steel design I found that it doesn't design Aluminum sections but I could design the steel sections,

and in the model to get a joint I got a multi beams instead of one continued beam (I'm talking about the Aluminum beams),

so how can I check the design of the Aluminum beams????

kindly find the attached STAAD file

thanks a lot in advance