Only one account showing on Google+ Android app
Version 1.0.2 is out, and appears that it's going to fix your issue.

From the release notes:


  What's in this version: 
  
  
  Spiffy new profile icon on the menu screen
  Handle multiple Gmail accounts on first sign in 
  Minor UI polish
  


(emphasis mine)

Unfortunately, I don't have my own invitation to Google+, so I'm not able to test this.