Salamander (LIFE FORCE) is a different Konami brand... it has a completely different story, since it tells that you're actually fighting with your spaceship inside a living creature, and AFAIK it's not related at all with Nemesis (GRADIUS) apart from the spaceship that could be the old Vic Viper.
The original arcade version of Nemesis had only one way of upgrading your spaceship... no selection between ripple fire and laser, or between force field and helpers... just laser and that helpers globe that stands in front of the Vic Viper. You were supposed to play it with three buttons... one for firing, another one for choosing the upgrades and a third button for... throwing missiles

After then, AFAIK in every Gradius game when you have acquired the missiles powerup, the missiles are thrown while you are firing.
Don't worry BTW since you are in good company

for many years I believed that Salamander was the sequel of Nemesis
BOTTOM LINE: If you own a Wii Console, love Gradius and live in Europe... don't miss the opportunity of buying "Gradius II" for the PC-Engine from the Virtual Console Channel. It's 9,00 Euro but you won't regret that
