I am not 100% sure but I think military starbases grant attack and defense bonuses to your ships if they are within it's zone of influence, so you won't see the starbase fire during your tactical combat view, instead your ships will have the attack and defense boosted according to wich module you have upgraded on your starbase. Although it would be cool to see attacks from nearby starbases in tactical sceen... maybe enven a representation of a far away station with a mniature starbase in the background of the tactical screen, hehe...

Hmm I seem to recall the original DL game to allow this, it seems like a feature that should definately be looked into.  If my ships are sitting on top of a starbase that has battle stations, the starbase's attack/defense should be added to the fleet if the fleet has logistical space for it.