Longshot - the commando is pretty tricky to set up due to the fact that it has to cast most of its abilities. I'm on vacation now but when I get back I might be able to put something together to illustrate how my commando is set up. You should be able to get the same DPS as you are getting with your vanguards.

Also, the first HM that I cleared was Taral V. Dulfy.net has a pretty good strategy for how to do this and I found her guides were spot on. It's really difficult in starter gear but once you gear up a bit it starts getting easier I promise! You also might want to consider augmenting your gear with reflex (aim) or overkill (power) augments.