So you need active sensors and fire control range from launching the missiles to them hitting?
So...the target has to stay painted with active sensors the entire time, from launch to impact, or the missiles detonate.
In theory, you could use a "spotter" vessel with powerful active sensors and another group of low-emission missile boats from a different direction. The missile boats would need FC but not active sensors. However, if your spotter ship gets destroyed (or even just the active sensor knocked out), your missile boats are useless and any in-flight missiles detonate.
The exception to that is what I mentioned above, that if you have any kind of onboard sensors on the missiles themselves, they'll go into tracking mode and continue their current trajectory with their sensors hunting for new targets.
One use for this would be to create missiles with onboard sensors, "flash" the enemy with active sensors long enough to get a lock and fire your salvo, then turn off active sensors and scoot to a different area to set up again. Problem being, as soon as you flash active, so will the enemy and they'll keep theirs on. So you'll need a low-tonnage, low-emission vehicle for that to work well.
Yet another option would be active sensor drones, fired into the general area of the hostiles, to create a temporary sensor "web" for targeting.